Add ability to null asset broadcasting from AJAX

modules/system/traits/AssetMaker.php

@@ -28,6 +28,17 @@ trait AssetMaker
      */
     public $assetPath;
 
+    /**
+     * Disables the use, and subequent broadcast, of assets. This is useful
+     * to call during an AJAX request to speed things up. This method works
+     * by specifically targeting the hasAssetsDefined method.
+     * @return void
+     */
+    public function clearAssetDefinitions()
+    {
+        $this->assets = ['js'=>[], 'css'=>[], 'rss'=>[]];
+    }
+
     /**
      * Outputs <link> and <script> tags to load assets previously added with addJs and addCss method calls
      * @param string $type Return an asset collection of a given type (css, rss, js) or null for all.