Port everything to class framework

The last patch in the sequence. Every place that was previously
setting prototype has been ported to Lang.Class, to make code more
concise and allow for better toString().

https://bugzilla.gnome.org/show_bug.cgi?id=664436

js/ui/lightbox.js

@@ -30,11 +30,9 @@ const Tweener = imports.ui.tweener;
  * @container and will track any changes in its size. You can override
  * this by passing an explicit width and height in @params.
  */
-function Lightbox(container, params) {
-    this._init(container, params);
-}
+const Lightbox = new Lang.Class({
+    Name: 'Lightbox',
 
-Lightbox.prototype = {
     _init : function(container, params) {
         params = Params.parse(params, { inhibitEvents: false,
                                         width: null,
@@ -196,4 +194,4 @@ Lightbox.prototype = {
 
         this.highlight(null);
     }
-};
+});