Refactor components for the main content section

Each conversation views now manages its own separate elements
rather than all binding to a shared #conversation element, and
similarly for message composition ui.

Also includes the beginnings of group creation UI (not working yet),
featuring bootstrap-tagsinput field for entering group recipients

js/views/message_list_view.js

@@ -6,10 +6,6 @@ var Whisper = Whisper || {};
   Whisper.MessageListView = Whisper.ListView.extend({
     tagName: 'ul',
     className: 'discussion',
-    itemView: Whisper.MessageView,
-
-    render: function() {
-      $('#discussion').html('').append(this.el);
-    }
+    itemView: Whisper.MessageView
   });
 })();