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/polkitAuthenticationAgent.js

@@ -335,11 +335,9 @@ const AuthenticationDialog = new Lang.Class({
 });
 Signals.addSignalMethods(AuthenticationDialog.prototype);
 
-function AuthenticationAgent() {
-    this._init();
-}
+const AuthenticationAgent = new Lang.Class({
+    Name: 'AuthenticationAgent',
 
-AuthenticationAgent.prototype = {
     _init: function() {
         this._native = new Shell.PolkitAuthenticationAgent();
         this._native.connect('initiate', Lang.bind(this, this._onInitiate));
@@ -400,7 +398,7 @@ AuthenticationAgent.prototype = {
             this._reallyCompleteRequest(wasDismissed);
         }
     }
-}
+});
 
 function init() {
     let agent = new AuthenticationAgent();