add locale service to GUI. minor cleanup of controller.

gui/index.html

@@ -868,6 +868,7 @@
   <script src="scripts/syncthing/core/filters/basenameFilter.js"></script>
   <script src="scripts/syncthing/core/filters/binaryFilter.js"></script>
   <script src="scripts/syncthing/core/filters/naturalFilter.js"></script>
+  <script src="scripts/syncthing/core/services/localeService.js"></script>
 
   <script src="assets/lang/valid-langs.js"></script>
   <script src="scripts/syncthing/app.js"></script>