removed backbone from VS solution,

renamed NzbDrone.Backbone to UI

UI/Missing/MissingModel.js

@@ -0,0 +1,12 @@
+define(['app'], function (app) {
+    NzbDrone.Missing.MissingModel = Backbone.Model.extend({
+        mutators: {
+            bestDateString: function () {
+                return bestDateString(this.get('airDate'));
+            },
+            paddedEpisodeNumber: function(){
+                return this.get('episodeNumber');
+            }
+        }
+    });
+});