MDL-51222 Javascript: Trigger events for filters on DOM insertion

When nodes are added to the dom, they may need to be re-processed by a JS based
filter. To do this we need to trigger the legacy YUI event filter-content-updated.

To make this easier I added some wrappers to template that will insert the node, run any
JS and trigger the event.

I also changed existing yui code to call the amd function to trigger the event. This way
all jquery and yui listeners will always be notified.

lib/amd/src/event.js

@@ -0,0 +1,52 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Global registry of core events that can be triggered/listened for.
+ *
+ * @module     core/event
+ * @package    core
+ * @class      event
+ * @copyright  2015 Damyon Wiese <damyon@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @since      3.0
+ */
+define([ 'jquery', 'core/yui' ],
+       function($, Y) {
+
+    return /** @alias module:core/event */ {
+        // Public variables and functions.
+        /**
+         * Trigger an event using both JQuery and YUI
+         *
+         * @method notifyFilterContentUpdated
+         * @param {string}|{JQuery} nodes - Selector or list of elements that were inserted.
+         */
+        notifyFilterContentUpdated: function(nodes) {
+            nodes = $(nodes);
+            Y.use('event', 'moodle-core-event', function(Y) {
+                // Trigger it the JQuery way.
+                $('document').trigger(M.core.event.FILTER_CONTENT_UPDATED, nodes);
+
+                // Create a YUI NodeList from our JQuery Object.
+                var yuiNodes = new Y.NodeList(nodes.get());
+
+                // And again for YUI.
+                Y.fire(M.core.event.FILTER_CONTENT_UPDATED, { nodes: yuiNodes });
+            });
+        },
+
+    };
+});