fix(settings): l10n of window title

'Settings' does not exist in the localisation files, but 'nav.settings' does.

Author: richardschneider

js/router.js

@@ -454,6 +454,6 @@ module.exports = Backbone.Router.extend({
       bodyID: 'userPage'
     });
 
-    app.appBar.setTitle(window.polyglot.t('Settings'));
+    app.appBar.setTitle(window.polyglot.t('nav.settings'));
   }
 });