Use consistent boiler plate throughout js files

js/views/message_list_view.js

@@ -13,10 +13,9 @@
  * You should have received a copy of the GNU Lesser General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-var Whisper = Whisper || {};
-
 (function () {
     'use strict';
+    window.Whisper = window.Whisper || {};
 
     Whisper.MessageListView = Whisper.ListView.extend({
         tagName: 'ul',