Settings save when changed only

UI/Settings/SettingsModel.js

@@ -1,6 +1,9 @@
 "use strict";
-define(['app'], function () {
+define(['app',
+        'Mixins/SaveIfChangedModel'], function () {
     NzbDrone.Settings.SettingsModel = Backbone.Model.extend({
         url: NzbDrone.Constants.ApiRoot + '/settings'
     });
+
+    _.extend(NzbDrone.Settings.SettingsModel.prototype, NzbDrone.Mixins.SaveIfChangedModel);
 });