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/endSessionDialog.js

@@ -142,11 +142,9 @@ function findAppFromInhibitor(inhibitor) {
     return app;
 }
 
-function ListItem(app, reason) {
-    this._init(app, reason);
-}
+const ListItem = new Lang.Class({
+    Name: 'ListItem',
 
-ListItem.prototype = {
     _init: function(app, reason) {
         this._app = app;
         this._reason = reason;
@@ -192,7 +190,7 @@ ListItem.prototype = {
         this.emit('activate');
         this._app.activate();
     }
-};
+});
 Signals.addSignalMethods(ListItem.prototype);
 
 // The logout timer only shows updates every 10 seconds