Extend action-log and subclass it as log widget (#5078)

* Extended action-log and subclassed it as log widget

* Do not rename LogWidget class

* Removed unneeded variable declaration

core/modules/widgets/log.js

@@ -0,0 +1,30 @@
+/*\
+title: $:/core/modules/widgets/log.js
+type: application/javascript
+module-type: widget-subclass
+
+Widget to log debug messages
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+exports.baseClass = "action-log";
+
+exports.name = "log";
+
+exports.constructor = function(parseTreeNode,options) {
+	this.initialise(parseTreeNode,options);
+}
+
+exports.prototype = {};
+
+exports.prototype.render = function(event) {
+	Object.getPrototypeOf(Object.getPrototypeOf(this)).render.call(this,event);	
+	Object.getPrototypeOf(Object.getPrototypeOf(this)).log.call(this);
+}
+
+})();