diff --git a/system/src/Grav/Common/Assets.old.php b/system/src/Grav/Common/Assets.old.php
deleted file mode 100644
index 247605ba6..000000000
--- a/system/src/Grav/Common/Assets.old.php
+++ /dev/null
@@ -1,1438 +0,0 @@
-<?php
-/**
- * @package    Grav.Common
- *
- * @copyright  Copyright (C) 2015 - 2018 Trilby Media, LLC. All rights reserved.
- * @license    MIT License; see LICENSE file for details.
- */
-
-namespace Grav\Common;
-
-use Closure;
-use Exception;
-use FilesystemIterator;
-use Grav\Common\Config\Config;
-use RecursiveDirectoryIterator;
-use RecursiveIteratorIterator;
-use RegexIterator;
-use RocketTheme\Toolbox\ResourceLocator\UniformResourceLocator;
-
-define('CSS_ASSET', true);
-define('JS_ASSET', false);
-
-class Assets
-{
-
-
-    /** @const Regex to match CSS urls */
-    const CSS_URL_REGEX = '{url\(([\'\"]?)(.*?)\1\)}';
-
-    /** @const Regex to match CSS sourcemap comments */
-    const CSS_SOURCEMAP_REGEX = '{\/\*# (.*?) \*\/}';
-
-    /** @const Regex to match CSS import content */
-    const CSS_IMPORT_REGEX = '{@import(.*?);}';
-
-    /**
-     * @const Regex to match <script> or <style> tag when adding inline style/script. Note that this only supports a
-     * single tag, so the check is greedy to avoid issues in JS.
-     */
-    const HTML_TAG_REGEX = '#(<([A-Z][A-Z0-9]*)>)+(.*)(<\/\2>)#is';
-
-
-    /**
-     * Closure used by the pipeline to fetch assets.
-     *
-     * Useful when file_get_contents() function is not available in your PHP
-     * installation or when you want to apply any kind of preprocessing to
-     * your assets before they get pipelined.
-     *
-     * The closure will receive as the only parameter a string with the path/URL of the asset and
-     * it should return the content of the asset file as a string.
-     *
-     * @var Closure
-     */
-    protected $fetch_command;
-
-    // Configuration toggles to enable/disable the pipelining feature
-    protected $css_pipeline = false;
-    protected $css_pipeline_include_externals = true;
-    protected $css_pipeline_before_excludes = true;
-    protected $js_pipeline = false;
-    protected $js_pipeline_include_externals = true;
-    protected $js_pipeline_before_excludes = true;
-
-    // The asset holding arrays
-    protected $collections = [];
-    protected $css = [];
-    protected $js = [];
-    protected $inline_css = [];
-    protected $inline_js = [];
-    protected $imports = [];
-
-    // Some configuration variables
-    protected $config;
-    protected $base_url;
-    protected $timestamp = '';
-    protected $assets_dir;
-    protected $assets_url;
-
-    // Default values for pipeline settings
-    protected $css_minify = true;
-    protected $css_minify_windows = false;
-    protected $css_rewrite = true;
-    protected $js_minify = true;
-
-    // Arrays to hold assets that should NOT be pipelined
-    protected $css_no_pipeline = [];
-    protected $js_no_pipeline = [];
-
-    /**
-     * Assets constructor.
-     *
-     * @param array $options
-     */
-    public function __construct(array $options = [])
-    {
-        // Forward config options
-        if ($options) {
-            $this->config((array)$options);
-        }
-    }
-
-    /**
-     * Set up configuration options.
-     *
-     * All the class properties except 'js' and 'css' are accepted here.
-     * Also, an extra option 'autoload' may be passed containing an array of
-     * assets and/or collections that will be automatically added on startup.
-     *
-     * @param  array $config Configurable options.
-     *
-     * @return $this
-     * @throws \Exception
-     */
-    public function config(array $config)
-    {
-        // Set pipeline modes
-        if (isset($config['css_pipeline'])) {
-            $this->css_pipeline = $config['css_pipeline'];
-        }
-
-        if (isset($config['css_pipeline_include_externals'])) {
-            $this->css_pipeline_include_externals = $config['css_pipeline_include_externals'];
-        }
-
-        if (isset($config['css_pipeline_before_excludes'])) {
-            $this->css_pipeline_before_excludes = $config['css_pipeline_before_excludes'];
-        }
-
-        if (isset($config['js_pipeline'])) {
-            $this->js_pipeline = $config['js_pipeline'];
-        }
-
-        if (isset($config['js_pipeline_include_externals'])) {
-            $this->js_pipeline_include_externals = $config['js_pipeline_include_externals'];
-        }
-
-        if (isset($config['js_pipeline_before_excludes'])) {
-            $this->js_pipeline_before_excludes = $config['js_pipeline_before_excludes'];
-        }
-
-        // Pipeline requires public dir
-        if (($this->js_pipeline || $this->css_pipeline) && !is_dir($this->assets_dir)) {
-            throw new \Exception('Assets: Public dir not found');
-        }
-
-        // Set custom pipeline fetch command
-        if (isset($config['fetch_command']) && ($config['fetch_command'] instanceof Closure)) {
-            $this->fetch_command = $config['fetch_command'];
-        }
-
-        // Set CSS Minify state
-        if (isset($config['css_minify'])) {
-            $this->css_minify = $config['css_minify'];
-        }
-
-        if (isset($config['css_minify_windows'])) {
-            $this->css_minify_windows = $config['css_minify_windows'];
-        }
-
-        if (isset($config['css_rewrite'])) {
-            $this->css_rewrite = $config['css_rewrite'];
-        }
-
-        // Set JS Minify state
-        if (isset($config['js_minify'])) {
-            $this->js_minify = $config['js_minify'];
-        }
-
-        // Set collections
-        if (isset($config['collections']) && is_array($config['collections'])) {
-            $this->collections = $config['collections'];
-        }
-
-        // Autoload assets
-        if (isset($config['autoload']) && is_array($config['autoload'])) {
-            foreach ($config['autoload'] as $asset) {
-                $this->add($asset);
-            }
-        }
-
-        // Set timestamp
-        if (isset($config['enable_asset_timestamp']) && $config['enable_asset_timestamp'] === true) {
-            $this->timestamp = Grav::instance()['cache']->getKey();
-        }
-
-        return $this;
-    }
-
-    /**
-     * Initialization called in the Grav lifecycle to initialize the Assets with appropriate configuration
-     */
-    public function init()
-    {
-        $grav = Grav::instance();
-        /** @var Config $config */
-        $config = $grav['config'];
-        $base_url = $grav['base_url'];
-        $asset_config = (array)$config->get('system.assets');
-
-        /** @var UniformResourceLocator $locator */
-        $locator = $grav['locator'];
-        $this->assets_dir = $locator->findResource('asset://') . DS;
-        $this->assets_url = $locator->findResource('asset://', false);
-
-        $this->config($asset_config);
-        $this->base_url = ($config->get('system.absolute_urls') ? '' : '/') . ltrim(ltrim($base_url, '/') . '/', '/');
-
-        // Register any preconfigured collections
-        foreach ($config->get('system.assets.collections', []) as $name => $collection) {
-            $this->registerCollection($name, (array)$collection);
-        }
-    }
-
-    /**
-     * Add an asset or a collection of assets.
-     *
-     * It automatically detects the asset type (JavaScript, CSS or collection).
-     * You may add more than one asset passing an array as argument.
-     *
-     * @param  mixed $asset
-     * @param  int   $priority the priority, bigger comes first
-     * @param  bool  $pipeline false if this should not be pipelined
-     *
-     * @return $this
-     */
-    public function add($asset, $priority = null, $pipeline = true)
-    {
-        // More than one asset
-        if (is_array($asset)) {
-            foreach ($asset as $a) {
-                $this->add($a, $priority, $pipeline);
-            }
-        } elseif (isset($this->collections[$asset])) {
-            $this->add($this->collections[$asset], $priority, $pipeline);
-        } else {
-            // Get extension
-            $extension = pathinfo(parse_url($asset, PHP_URL_PATH), PATHINFO_EXTENSION);
-
-            // JavaScript or CSS
-            if (strlen($extension) > 0) {
-                $extension = strtolower($extension);
-                if ($extension === 'css') {
-                    $this->addCss($asset, $priority, $pipeline);
-                } elseif ($extension === 'js') {
-                    $this->addJs($asset, $priority, $pipeline);
-                }
-            }
-        }
-
-        return $this;
-    }
-
-    /**
-     * Add an asset to its assembly.
-     *
-     * It checks for duplicates.
-     * You may add more than one asset passing an array as argument.
-     * The third argument may alternatively contain an array of options which take precedence over positional
-     * arguments.
-     *
-     * @param  array   $assembly the array assembling the assets
-     * @param  mixed   $asset
-     * @param  int     $priority the priority, bigger comes first
-     * @param  bool    $pipeline false if this should not be pipelined
-     * @param  string  $loading  how the asset is loaded (async/defer/inline, for CSS: only inline)
-     * @param  string  $group    name of the group
-     *
-     * @return $this
-     */
-    protected function addTo(&$assembly, $asset, $priority = null, $pipeline = true, $loading = null, $group = null)
-    {
-        if (is_array($asset)) {
-            foreach ($asset as $a) {
-                $this->addTo($assembly, $a, $priority, $pipeline, $loading, $group);
-            }
-
-            return $this;
-        } elseif (isset($this->collections[$asset])) {
-            $this->addTo($assembly, $this->collections[$asset], $priority, $pipeline, $loading, $group);
-
-            return $this;
-        }
-
-        $query = [];
-
-        $modified = false;
-        $remote = $this->isRemoteLink($asset);
-        if (!$remote) {
-
-            $asset_parts = parse_url($asset);
-            if (isset($asset_parts['query'])) {
-                $query[] = $asset_parts['query'];
-                unset($asset_parts['query']);
-                $asset = Uri::buildUrl($asset_parts);
-            }
-
-
-            $modified = $this->getLastModificationTime($asset);
-            $asset = $this->buildLocalLink($asset);
-        }
-
-        // Check for existence
-        if ($asset === false) {
-            return $this;
-        }
-
-        $data = [
-            'asset'    => $asset,
-            'remote'   => $remote,
-            'priority' => intval($priority ?: 10),
-            'order'    => count($assembly),
-            'pipeline' => (bool) $pipeline,
-            'loading'  => $loading ?: '',
-            'group'    => $group ?: 'head',
-            'modified' => $modified,
-            'query'    => implode('&', $query),
-        ];
-
-        // check for dynamic array and merge with defaults
-        if (func_num_args() > 2) {
-            $dynamic_arg = func_get_arg(2);
-            if (is_array($dynamic_arg)) {
-                $data = array_merge($data, $dynamic_arg);
-            }
-        }
-
-        $key = md5($asset);
-        if ($asset) {
-            $assembly[$key] = $data;
-        }
-
-        return $this;
-    }
-
-    /**
-     * Add a CSS asset.
-     *
-     * It checks for duplicates.
-     * You may add more than one asset passing an array as argument.
-     * The second argument may alternatively contain an array of options which take precedence over positional
-     * arguments.
-     *
-     * @param  mixed   $asset
-     * @param  int     $priority the priority, bigger comes first
-     * @param  bool    $pipeline false if this should not be pipelined
-     * @param  string  $group
-     * @param  string  $loading  how the asset is loaded (async/defer/inline, for CSS: only inline)
-     *
-     * @return $this
-     */
-    public function addCss($asset, $priority = null, $pipeline = true, $group = null, $loading = null)
-    {
-        return $this->addTo($this->css, $asset, $priority, $pipeline, $loading, $group);
-    }
-
-    /**
-     * Add a JavaScript asset.
-     *
-     * It checks for duplicates.
-     * You may add more than one asset passing an array as argument.
-     * The second argument may alternatively contain an array of options which take precedence over positional
-     * arguments.
-     *
-     * @param  mixed  $asset
-     * @param  int    $priority the priority, bigger comes first
-     * @param  bool   $pipeline false if this should not be pipelined
-     * @param  string $loading  how the asset is loaded (async/defer)
-     * @param  string $group    name of the group
-     *
-     * @return $this
-     */
-    public function addJs($asset, $priority = null, $pipeline = true, $loading = null, $group = null)
-    {
-        return $this->addTo($this->js, $asset, $priority, $pipeline, $loading, $group);
-    }
-
-    /**
-     * Convenience wrapper for async loading of JavaScript
-     *
-     * @param        $asset
-     * @param int    $priority
-     * @param bool   $pipeline
-     * @param string $group name of the group
-     *
-     * @deprecated Please use dynamic method with ['loading' => 'async']
-     *
-     * @return \Grav\Common\Assets
-     */
-    public function addAsyncJs($asset, $priority = null, $pipeline = true, $group = null)
-    {
-        return $this->addJs($asset, $priority, $pipeline, 'async', $group);
-    }
-
-    /**
-     * Convenience wrapper for deferred loading of JavaScript
-     *
-     * @param        $asset
-     * @param        $asset
-     * @param int    $priority
-     * @param bool   $pipeline
-     * @param string $group name of the group
-     *
-     * @deprecated Please use dynamic method with ['loading' => 'defer']
-     *
-     * @return \Grav\Common\Assets
-     */
-    public function addDeferJs($asset, $priority = null, $pipeline = true, $group = null)
-    {
-        return $this->addJs($asset, $priority, $pipeline, 'defer', $group);
-    }
-
-    /**
-     * Add an inline CSS asset.
-     *
-     * It checks for duplicates.
-     * For adding chunks of string-based inline CSS
-     *
-     * @param  mixed $asset
-     * @param  int   $priority the priority, bigger comes first
-     * @param null   $group
-     *
-     * @return $this
-     */
-    public function addInlineCss($asset, $priority = null, $group = null)
-    {
-        $asset = trim($asset);
-
-        if (is_a($asset, 'Twig_Markup')) {
-            preg_match(self::HTML_TAG_REGEX, $asset, $matches);
-            if (isset($matches[3])) {
-                $asset = $matches[3];
-            }
-        }
-
-        $data = [
-            'priority' => intval($priority ?: 10),
-            'order'    => count($this->inline_css),
-            'asset'    => $asset,
-            'group'    => $group ?: 'head'
-        ];
-
-        // check for dynamic array and merge with defaults
-        if (func_num_args() == 2) {
-            $dynamic_arg = func_get_arg(1);
-            if (is_array($dynamic_arg)) {
-                $data = array_merge($data, $dynamic_arg);
-            }
-        }
-
-        $key = md5($asset);
-        if ($asset && is_string($asset) && !array_key_exists($key, $this->inline_css)) {
-            $this->inline_css[$key] = $data;
-        }
-
-        return $this;
-    }
-
-    /**
-     * Add an inline JS asset.
-     *
-     * It checks for duplicates.
-     * For adding chunks of string-based inline JS
-     *
-     * @param  mixed $asset
-     * @param  int $priority the priority, bigger comes first
-     * @param string $group name of the group
-     * @param null $attributes
-     *
-     * @return $this
-     */
-    public function addInlineJs($asset, $priority = null, $group = null, $attributes = null)
-    {
-        $asset = trim($asset);
-
-        if (is_a($asset, 'Twig_Markup')) {
-            preg_match(self::HTML_TAG_REGEX, $asset, $matches);
-            if (isset($matches[3])) {
-                $asset = $matches[3];
-            }
-        }
-
-        $data = [
-            'asset'    => $asset,
-            'priority' => intval($priority ?: 10),
-            'order'    => count($this->js),
-            'group'    => $group ?: 'head',
-            'type'     => $attributes ?: '',
-        ];
-
-        // check for dynamic array and merge with defaults
-        if (func_num_args() == 2) {
-            $dynamic_arg = func_get_arg(1);
-            if (is_array($dynamic_arg)) {
-                $data = array_merge($data, $dynamic_arg);
-            }
-        }
-
-        $key = md5($asset);
-        if ($asset && is_string($asset) && !array_key_exists($key, $this->inline_js)) {
-            $this->inline_js[$key] = $data;
-        }
-
-        return $this;
-    }
-
-    /**
-     * Build the CSS link tags.
-     *
-     * @param  string $group name of the group
-     * @param  array  $attributes
-     *
-     * @return string
-     */
-    public function css($group = 'head', $attributes = [])
-    {
-        if (!$this->css && !$this->inline_css) {
-            return null;
-        }
-
-        // Sort array by priorities (larger priority first)
-        if (Grav::instance()) {
-            uasort($this->css, array($this, 'sortAssetsByPriorityThenOrder'));
-            uasort($this->inline_css, array($this, 'sortAssetsByPriorityThenOrder'));
-        }
-
-        $inlineGroup = array_key_exists('loading', $attributes) && $attributes['loading'] === 'inline';
-
-        $attributes = $this->attributes(array_merge(['type' => 'text/css', 'rel' => 'stylesheet'], $attributes));
-
-        $output = '';
-        $inline_css = '';
-
-        if ($this->css_pipeline) {
-            $pipeline_result = $this->pipelineCss($group, !$inlineGroup);
-            $pipeline_html = ($inlineGroup ? '' : '<link href="' . $pipeline_result . '"' . $attributes . ' />' . "\n");
-
-            if ($this->css_pipeline_before_excludes && $pipeline_result) {
-                if ($inlineGroup) {
-                    $inline_css .= $pipeline_result;
-                }
-                else {
-                    $output .= $pipeline_html;
-                }
-            }
-            foreach ($this->css_no_pipeline as $file) {
-                if ($group && $file['group'] == $group) {
-                    if ($file['loading'] === 'inline') {
-                        $inline_css .= $this->gatherLinks([$file], CSS_ASSET) . "\n";
-                    }
-                    else {
-                        $media = isset($file['media']) ? sprintf(' media="%s"', $file['media']) : '';
-                        $output .= '<link href="' . $file['asset'] . $this->getQuerystring($file) . '"' . $attributes . $media . ' />' . "\n";
-                    }
-                }
-            }
-            if (!$this->css_pipeline_before_excludes && $pipeline_result) {
-                if ($inlineGroup) {
-                    $inline_css .= $pipeline_result;
-                }
-                else {
-                    $output .= $pipeline_html;
-                }
-            }
-        } else {
-            foreach ($this->css as $file) {
-                if ($group && $file['group'] == $group) {
-                    if ($inlineGroup || $file['loading'] === 'inline') {
-                        $inline_css .= $this->gatherLinks([$file], CSS_ASSET) . "\n";
-                    }
-                    else {
-                        $media = isset($file['media']) ? sprintf(' media="%s"', $file['media']) : '';
-                        $output .= '<link href="' . $file['asset'] . $this->getQuerystring($file) . '"' . $attributes . $media . ' />' . "\n";
-                    }
-                }
-            }
-        }
-
-        // Render Inline CSS
-        foreach ($this->inline_css as $inline) {
-            if ($group && $inline['group'] == $group) {
-                $inline_css .= $inline['asset'] . "\n";
-            }
-        }
-
-        if ($inline_css) {
-            $output .= "\n<style>\n" . $inline_css . "\n</style>\n";
-        }
-
-
-        return $output;
-    }
-
-    /**
-     * Build the JavaScript script tags.
-     *
-     * @param  string $group name of the group
-     * @param  array  $attributes
-     *
-     * @return string
-     */
-    public function js($group = 'head', $attributes = [])
-    {
-        if (!$this->js && !$this->inline_js) {
-            return null;
-        }
-
-        // Sort array by priorities (larger priority first)
-        uasort($this->js, array($this, 'sortAssetsByPriorityThenOrder'));
-        uasort($this->inline_js, array($this, 'sortAssetsByPriorityThenOrder'));
-
-        $inlineGroup = array_key_exists('loading', $attributes) && $attributes['loading'] === 'inline';
-
-        $attributes = $this->attributes($attributes);
-
-        $output = '';
-        $inline_js = '';
-
-        if ($this->js_pipeline) {
-            $pipeline_result = $this->pipelineJs($group, !$inlineGroup);
-            $pipeline_html = ($inlineGroup ? '' : '<script src="' . $pipeline_result . '"' . $attributes . ' ></script>' . "\n");
-
-            if ($this->js_pipeline_before_excludes && $pipeline_result) {
-                if ($inlineGroup) {
-                    $inline_js .= $pipeline_result;
-                }
-                else {
-                    $output .= $pipeline_html;
-                }
-            }
-            foreach ($this->js_no_pipeline as $file) {
-                if ($group && $file['group'] == $group) {
-                    if ($file['loading'] === 'inline') {
-                        $inline_js .= $this->gatherLinks([$file], JS_ASSET) . "\n";
-                    }
-                    else {
-                        $output .= '<script src="' . $file['asset'] . $this->getQuerystring($file) . '"' . $attributes . ' ' . $file['loading'] . '></script>' . "\n";
-                    }
-                }
-            }
-            if (!$this->js_pipeline_before_excludes && $pipeline_result) {
-                if ($inlineGroup) {
-                    $inline_js .= $pipeline_result;
-                }
-                else {
-                    $output .= $pipeline_html;
-                }
-            }
-        } else {
-            foreach ($this->js as $file) {
-                if ($group && $file['group'] == $group) {
-                    if ($inlineGroup || $file['loading'] === 'inline') {
-                        $inline_js .= $this->gatherLinks([$file], JS_ASSET) . "\n";
-                    }
-                    else {
-                        $output .= '<script src="' . $file['asset'] . $this->getQuerystring($file) . '"' . $attributes . ' ' . $file['loading'] . '></script>' . "\n";
-                    }
-                }
-            }
-        }
-
-        // Render Inline JS
-        foreach ($this->inline_js as $inline) {
-            if ($group && $inline['group'] == $group) {
-                $inline_js .= $inline['asset'] . "\n";
-            }
-        }
-
-        if ($inline_js) {
-            $attribute_string = isset($inline) && $inline['type'] ? " type=\"" . $inline['type'] . "\"" : '';
-            $output .= "\n<script" . $attribute_string . ">\n" . $inline_js . "\n</script>\n";
-        }
-
-        return $output;
-    }
-
-    /**
-     * Minify and concatenate CSS
-     *
-     * @param string $group
-     * @param bool $returnURL  true if pipeline should return the URL, otherwise the content
-     *
-     * @return bool|string     URL or generated content if available, else false
-     */
-    protected function pipelineCss($group = 'head', $returnURL = true)
-    {
-        // temporary list of assets to pipeline
-        $temp_css = [];
-
-        // clear no-pipeline assets lists
-        $this->css_no_pipeline = [];
-
-        // Compute uid based on assets and timestamp
-        $uid = md5(json_encode($this->css) . $this->css_minify . $this->css_rewrite . $group);
-        $file =  $uid . '.css';
-        $inline_file = $uid . '-inline.css';
-
-        $relative_path = "{$this->base_url}{$this->assets_url}/{$file}";
-
-        // If inline files exist set them on object
-        if (file_exists($this->assets_dir . $inline_file)) {
-            $this->css_no_pipeline = json_decode(file_get_contents($this->assets_dir . $inline_file), true);
-        }
-
-        // If pipeline exist return its URL or content
-        if (file_exists($this->assets_dir . $file)) {
-            if ($returnURL) {
-                return $relative_path . $this->getTimestamp();
-            }
-            else {
-                return file_get_contents($this->assets_dir . $file) . "\n";
-            }
-        }
-
-        // Remove any non-pipeline files
-        foreach ($this->css as $id => $asset) {
-            if ($asset['group'] == $group) {
-                if (!$asset['pipeline'] ||
-                    ($asset['remote'] && $this->css_pipeline_include_externals === false)) {
-                    $this->css_no_pipeline[$id] = $asset;
-                } else {
-                    $temp_css[$id] = $asset;
-                }
-            }
-        }
-
-        //if nothing found get out of here!
-        if (count($temp_css) == 0) {
-            return false;
-        }
-
-        // Write non-pipeline files out
-        if (!empty($this->css_no_pipeline)) {
-            file_put_contents($this->assets_dir . $inline_file, json_encode($this->css_no_pipeline));
-        }
-
-
-        $css_minify = $this->css_minify;
-
-        // If this is a Windows server, and minify_windows is false (default value) skip the
-        // minification process because it will cause Apache to die/crash due to insufficient
-        // ThreadStackSize in httpd.conf - See: https://bugs.php.net/bug.php?id=47689
-        if (strtoupper(substr(php_uname('s'), 0, 3)) === 'WIN' && !$this->css_minify_windows) {
-            $css_minify = false;
-        }
-
-        // Concatenate files
-        $buffer = $this->gatherLinks($temp_css, CSS_ASSET);
-        if ($css_minify) {
-            $minifier = new \MatthiasMullie\Minify\CSS();
-            $minifier->add($buffer);
-            $buffer = $minifier->minify();
-        }
-
-        // Write file
-        if (strlen(trim($buffer)) > 0) {
-            file_put_contents($this->assets_dir . $file, $buffer);
-
-            if ($returnURL) {
-                return $relative_path . $this->getTimestamp();
-            }
-            else {
-                return $buffer . "\n";
-            }
-        } else {
-            return false;
-        }
-    }
-
-    /**
-     * Minify and concatenate JS files.
-     *
-     * @param string $group
-     * @param bool $returnURL  true if pipeline should return the URL, otherwise the content
-     *
-     * @return bool|string     URL or generated content if available, else false
-     */
-    protected function pipelineJs($group = 'head', $returnURL = true)
-    {
-        // temporary list of assets to pipeline
-        $temp_js = [];
-
-        // clear no-pipeline assets lists
-        $this->js_no_pipeline = [];
-
-        // Compute uid based on assets and timestamp
-        $uid = md5(json_encode($this->js) . $this->js_minify . $group);
-        $file =  $uid . '.js';
-        $inline_file = $uid . '-inline.js';
-
-        $relative_path = "{$this->base_url}{$this->assets_url}/{$file}";
-
-        // If inline files exist set them on object
-        if (file_exists($this->assets_dir . $inline_file)) {
-            $this->js_no_pipeline = json_decode(file_get_contents($this->assets_dir . $inline_file), true);
-        }
-
-        // If pipeline exist return its URL or content
-        if (file_exists($this->assets_dir . $file)) {
-            if ($returnURL) {
-                return $relative_path . $this->getTimestamp();
-            }
-            else {
-                return file_get_contents($this->assets_dir . $file) . "\n";
-            }
-        }
-
-        // Remove any non-pipeline files
-        foreach ($this->js as $id => $asset) {
-            if ($asset['group'] == $group) {
-                if (!$asset['pipeline'] ||
-                    ($asset['remote'] && $this->js_pipeline_include_externals === false)) {
-                    $this->js_no_pipeline[] = $asset;
-                } else {
-                    $temp_js[$id] = $asset;
-                }
-            }
-        }
-
-        //if nothing found get out of here!
-        if (count($temp_js) == 0) {
-            return false;
-        }
-
-        // Write non-pipeline files out
-        if (!empty($this->js_no_pipeline)) {
-            file_put_contents($this->assets_dir . $inline_file, json_encode($this->js_no_pipeline));
-        }
-
-        // Concatenate files
-        $buffer = $this->gatherLinks($temp_js, JS_ASSET);
-        if ($this->js_minify) {
-            $minifier = new \MatthiasMullie\Minify\JS();
-            $minifier->add($buffer);
-            $buffer = $minifier->minify();
-        }
-
-        // Write file
-        if (strlen(trim($buffer)) > 0) {
-            file_put_contents($this->assets_dir . $file, $buffer);
-
-            if ($returnURL) {
-                return $relative_path . $this->getTimestamp();
-            }
-            else {
-                return $buffer . "\n";
-            }
-        } else {
-            return false;
-        }
-    }
-
-    /**
-     * Return the array of all the registered CSS assets
-     * If a $key is provided, it will try to return only that asset
-     * else it will return null
-     *
-     * @param null|string $key the asset key
-     * @return array
-     */
-    public function getCss($key = null)
-    {
-        if (!empty($key)) {
-            $asset_key = md5($key);
-            if (isset($this->css[$asset_key])) {
-                return $this->css[$asset_key];
-            } else {
-                return null;
-            }
-        }
-
-        return $this->css;
-    }
-
-    /**
-     * Return the array of all the registered JS assets
-     * If a $key is provided, it will try to return only that asset
-     * else it will return null
-     *
-     * @param null|string $key the asset key
-     * @return array
-     */
-    public function getJs($key = null)
-    {
-        if (!empty($key)) {
-            $asset_key = md5($key);
-            if (isset($this->js[$asset_key])) {
-                return $this->js[$asset_key];
-            } else {
-                return null;
-            }
-        }
-
-        return $this->js;
-    }
-
-    /**
-     * Set the whole array of CSS assets
-     *
-     * @param $css
-     */
-    public function setCss($css)
-    {
-        $this->css = $css;
-    }
-
-    /**
-     * Set the whole array of JS assets
-     *
-     * @param $js
-     */
-    public function setJs($js)
-    {
-        $this->js = $js;
-    }
-
-    /**
-     * Removes an item from the CSS array if set
-     *
-     * @param string $key  The asset key
-     */
-    public function removeCss($key)
-    {
-        $asset_key = md5($key);
-        if (isset($this->css[$asset_key])) {
-            unset($this->css[$asset_key]);
-        }
-    }
-
-    /**
-     * Removes an item from the JS array if set
-     *
-     * @param string $key  The asset key
-     */
-    public function removeJs($key)
-    {
-        $asset_key = md5($key);
-        if (isset($this->js[$asset_key])) {
-            unset($this->js[$asset_key]);
-        }
-    }
-
-    /**
-     * Return the array of all the registered collections
-     *
-     * @return array
-     */
-    public function getCollections()
-    {
-        return $this->collections;
-    }
-
-    /**
-     * Set the array of collections explicitly
-     *
-     * @param $collections
-     */
-    public function setCollection($collections)
-    {
-        $this->collections = $collections;
-    }
-
-    /**
-     * Determines if an asset exists as a collection, CSS or JS reference
-     *
-     * @param $asset
-     *
-     * @return bool
-     */
-    public function exists($asset)
-    {
-        if (isset($this->collections[$asset]) || isset($this->css[$asset]) || isset($this->js[$asset])) {
-            return true;
-        } else {
-            return false;
-        }
-    }
-
-    /**
-     * Add/replace collection.
-     *
-     * @param  string $collectionName
-     * @param  array  $assets
-     * @param bool    $overwrite
-     *
-     * @return $this
-     */
-    public function registerCollection($collectionName, Array $assets, $overwrite = false)
-    {
-        if ($overwrite || !isset($this->collections[$collectionName])) {
-            $this->collections[$collectionName] = $assets;
-        }
-
-        return $this;
-    }
-
-    /**
-     * Reset all assets.
-     *
-     * @return $this
-     */
-    public function reset()
-    {
-        return $this->resetCss()->resetJs();
-    }
-
-    /**
-     * Reset JavaScript assets.
-     *
-     * @return $this
-     */
-    public function resetJs()
-    {
-        $this->js = [];
-        $this->inline_js = [];
-
-        return $this;
-    }
-
-    /**
-     * Reset CSS assets.
-     *
-     * @return $this
-     */
-    public function resetCss()
-    {
-        $this->css = [];
-        $this->inline_css = [];
-
-        return $this;
-    }
-
-    /**
-     * Add all JavaScript assets within $directory
-     *
-     * @param  string $directory Relative to the Grav root path, or a stream identifier
-     *
-     * @return $this
-     */
-    public function addDirJs($directory)
-    {
-        return $this->addDir($directory, self::JS_REGEX);
-    }
-
-    /**
-     * Add all CSS assets within $directory
-     *
-     * @param  string $directory Relative to the Grav root path, or a stream identifier
-     *
-     * @return $this
-     */
-    public function addDirCss($directory)
-    {
-        return $this->addDir($directory, self::CSS_REGEX);
-    }
-
-    /**
-     * Add all assets matching $pattern within $directory.
-     *
-     * @param  string $directory Relative to the Grav root path, or a stream identifier
-     * @param  string $pattern   (regex)
-     *
-     * @return $this
-     * @throws Exception
-     */
-    public function addDir($directory, $pattern = self::DEFAULT_REGEX)
-    {
-        $root_dir = rtrim(ROOT_DIR, '/');
-
-        // Check if $directory is a stream.
-        if (strpos($directory, '://')) {
-            $directory = Grav::instance()['locator']->findResource($directory, null);
-        }
-
-        // Get files
-        $files = $this->rglob($root_dir . DIRECTORY_SEPARATOR . $directory, $pattern, $root_dir . '/');
-
-        // No luck? Nothing to do
-        if (!$files) {
-            return $this;
-        }
-
-        // Add CSS files
-        if ($pattern === self::CSS_REGEX) {
-            foreach ($files as $file) {
-                $this->addCss($file);
-            }
-
-            return $this;
-        }
-
-        // Add JavaScript files
-        if ($pattern === self::JS_REGEX) {
-            foreach ($files as $file) {
-                $this->addJs($file);
-            }
-
-            return $this;
-        }
-
-        // Unknown pattern.
-        foreach ($files as $asset) {
-            $this->add($asset);
-        }
-
-        return $this;
-    }
-
-    /**
-     * Determine whether a link is local or remote.
-     *
-     * Understands both "http://" and "https://" as well as protocol agnostic links "//"
-     *
-     * @param  string $link
-     *
-     * @return bool
-     */
-    protected function isRemoteLink($link)
-    {
-        $base = Grav::instance()['uri']->rootUrl(true);
-
-        // sanity check for local URLs with absolute URL's enabled
-        if (Utils::startsWith($link, $base)) {
-            return false;
-        }
-
-        return ('http://' === substr($link, 0, 7) || 'https://' === substr($link, 0, 8) || '//' === substr($link, 0,
-                2));
-    }
-
-    /**
-     * Build local links including grav asset shortcodes
-     *
-     * @param  string $asset    the asset string reference
-     * @param  bool   $absolute build absolute asset link
-     *
-     * @return string           the final link url to the asset
-     */
-    protected function buildLocalLink($asset, $absolute = false)
-    {
-        try {
-            $asset = Grav::instance()['locator']->findResource($asset, $absolute);
-        } catch (\Exception $e) {
-        }
-
-        $uri = $absolute ? $asset : $this->base_url . ltrim($asset, '/');
-        return $asset ? $uri : false;
-    }
-
-    /**
-     * Get the last modification time of asset
-     *
-     * @param  string $asset    the asset string reference
-     *
-     * @return string           the last modifcation time or false on error
-     */
-    protected function getLastModificationTime($asset)
-    {
-        $file = GRAV_ROOT . $asset;
-        if (Grav::instance()['locator']->isStream($asset)) {
-            $file = $this->buildLocalLink($asset, true);
-        }
-
-        return file_exists($file) ? filemtime($file) : false;
-    }
-
-    /**
-     * Build an HTML attribute string from an array.
-     *
-     * @param  array $attributes
-     *
-     * @return string
-     */
-    protected function attributes(array $attributes)
-    {
-        $html = '';
-        $no_key = ['loading'];
-
-        foreach ($attributes as $key => $value) {
-            // For numeric keys we will assume that the key and the value are the same
-            // as this will convert HTML attributes such as "required" to a correct
-            // form like required="required" instead of using incorrect numerics.
-            if (is_numeric($key)) {
-                $key = $value;
-            }
-            if (is_array($value)) {
-                $value = implode(' ', $value);
-            }
-
-            if (in_array($key, $no_key)) {
-                $element = htmlentities($value, ENT_QUOTES, 'UTF-8', false);
-            } else {
-                $element = $key . '="' . htmlentities($value, ENT_QUOTES, 'UTF-8', false) . '"';
-            }
-
-            $html .= ' ' . $element;
-        }
-
-        return $html;
-    }
-
-    /**
-     * Download and concatenate the content of several links.
-     *
-     * @param  array $links
-     * @param  bool  $css
-     *
-     * @return string
-     */
-    protected function gatherLinks(array $links, $css = true)
-    {
-        $buffer = '';
-
-
-        foreach ($links as $asset) {
-            $relative_dir = '';
-            $local = true;
-
-            $link = $asset['asset'];
-            $relative_path = $link;
-
-            if ($this->isRemoteLink($link)) {
-                $local = false;
-                if ('//' === substr($link, 0, 2)) {
-                    $link = 'http:' . $link;
-                }
-            } else {
-                // Fix to remove relative dir if grav is in one
-                if (($this->base_url != '/') && (strpos($this->base_url, $link) == 0)) {
-                    $base_url = '#' . preg_quote($this->base_url, '#') . '#';
-                    $relative_path = ltrim(preg_replace($base_url, '/', $link, 1), '/');
-                }
-
-                $relative_dir = dirname($relative_path);
-                $link = ROOT_DIR . $relative_path;
-            }
-
-            $file = ($this->fetch_command instanceof Closure) ? @$this->fetch_command->__invoke($link) : @file_get_contents($link);
-
-            // No file found, skip it...
-            if ($file === false) {
-                continue;
-            }
-
-            // Double check last character being
-            if (!$css) {
-                $file = rtrim($file, ' ;') . ';';
-            }
-
-            // If this is CSS + the file is local + rewrite enabled
-            if ($css && $local && $this->css_rewrite) {
-                $file = $this->cssRewrite($file, $relative_dir);
-            }
-
-            $file = rtrim($file) . PHP_EOL;
-            $buffer .= $file;
-        }
-
-        // Pull out @imports and move to top
-        if ($css) {
-            $buffer = $this->moveImports($buffer);
-        }
-
-        return $buffer;
-    }
-
-    /**
-     * Finds relative CSS urls() and rewrites the URL with an absolute one
-     *
-     * @param string $file          the css source file
-     * @param string $relative_path relative path to the css file
-     *
-     * @return mixed
-     */
-    protected function cssRewrite($file, $relative_path)
-    {
-        // Strip any sourcemap comments
-        $file = preg_replace(self::CSS_SOURCEMAP_REGEX, '', $file);
-
-        // Find any css url() elements, grab the URLs and calculate an absolute path
-        // Then replace the old url with the new one
-        $file = preg_replace_callback(self::CSS_URL_REGEX, function ($matches) use ($relative_path) {
-
-            $old_url = $matches[2];
-
-            // Ensure link is not rooted to webserver, a data URL, or to a remote host
-            if (Utils::startsWith($old_url, '/') || Utils::startsWith($old_url, 'data:') || $this->isRemoteLink($old_url)) {
-                return $matches[0];
-            }
-
-            $new_url = $this->base_url . ltrim(Utils::normalizePath($relative_path . '/' . $old_url), '/');
-
-            return str_replace($old_url, $new_url, $matches[0]);
-        }, $file);
-
-        return $file;
-    }
-
-    /**
-     * Moves @import statements to the top of the file per the CSS specification
-     *
-     * @param  string $file the file containing the combined CSS files
-     *
-     * @return string       the modified file with any @imports at the top of the file
-     */
-    protected function moveImports($file)
-    {
-        $this->imports = [];
-
-        $file = preg_replace_callback(self::CSS_IMPORT_REGEX, function ($matches) {
-            $this->imports[] = $matches[0];
-
-            return '';
-        }, $file);
-
-        return implode("\n", $this->imports) . "\n\n" . $file;
-    }
-
-    /**
-     * Recursively get files matching $pattern within $directory.
-     *
-     * @param  string $directory
-     * @param  string $pattern (regex)
-     * @param  string $ltrim   Will be trimmed from the left of the file path
-     *
-     * @return array
-     */
-    protected function rglob($directory, $pattern, $ltrim = null)
-    {
-        $iterator = new RegexIterator(new RecursiveIteratorIterator(new RecursiveDirectoryIterator($directory,
-            FilesystemIterator::SKIP_DOTS)), $pattern);
-        $offset = strlen($ltrim);
-        $files = [];
-
-        foreach ($iterator as $file) {
-            $files[] = substr($file->getPathname(), $offset);
-        }
-
-        return $files;
-    }
-
-    /**
-     * Sets the state of CSS Pipeline
-     *
-     * @param boolean $value
-     */
-    public function setCssPipeline($value)
-    {
-        $this->css_pipeline = (bool)$value;
-    }
-
-    /**
-     * Sets the state of JS Pipeline
-     *
-     * @param boolean $value
-     */
-    public function setJsPipeline($value)
-    {
-        $this->js_pipeline = (bool)$value;
-    }
-
-    /**
-     * Explicitly set's a timestamp for assets
-     *
-     * @param $value
-     */
-    public function setTimestamp($value)
-    {
-        $this->timestamp = $value;
-    }
-
-    /**
-     * Get the timestamp for assets
-     *
-     * @return string
-     */
-    public function getTimestamp($include_join = true)
-    {
-        if ($this->timestamp) {
-            $timestamp = $include_join ? '?' . $this->timestamp : $this->timestamp;
-            return $timestamp;
-        }
-        return;
-    }
-
-    /**
-     *
-     *
-     * @param $asset
-     * @return string
-     */
-    public function getQuerystring($asset)
-    {
-        $querystring = '';
-
-        if (!empty($asset['query'])) {
-            if (Utils::contains($asset['asset'], '?')) {
-                $querystring .=  '&' . $asset['query'];
-            } else {
-               $querystring .= '?' . $asset['query'];
-            }
-        }
-
-        if ($this->timestamp) {
-            if (Utils::contains($asset['asset'], '?') || $querystring) {
-                $querystring .=  '&' . $this->timestamp;
-            } else {
-                $querystring .= '?' . $this->timestamp;
-            }
-        }
-
-        return $querystring;
-    }
-
-    /**
-     * @return string
-     */
-    public function __toString()
-    {
-        return '';
-    }
-
-    /**
-     * @param $a
-     * @param $b
-     *
-     * @return mixed
-     */
-    protected function sortAssetsByPriorityThenOrder($a, $b)
-    {
-        if ($a['priority'] == $b['priority']) {
-            return $a['order'] - $b['order'];
-        }
-
-        return $b['priority'] - $a['priority'];
-    }
-
-}