Fix new threads not appearing at top of inbox

When messages from someone not in your inbox arrived, that thread would
appear at the bottom of the inbox instead of the top.

// FREEBIE

js/views/inbox_view.js

@@ -92,7 +92,7 @@
                     collection : inboxCollection
                 }).render();
 
-                this.inboxListView.listenTo(inboxCollection, 'change:active_at', this.inboxListView.onChangeActiveAt);
+                this.inboxListView.listenTo(inboxCollection, 'add change:active_at', this.inboxListView.onChangeActiveAt);
 
                 new SocketView().render().$el.appendTo(this.$('.socket-status'));