remote-search: apply sort-order from GSettings

Sort providers according to the GSettings state, and make sure to reload
them as soon as the sort order changes.

https://bugzilla.gnome.org/show_bug.cgi?id=687491

js/ui/viewSelector.js

@@ -96,6 +96,7 @@ const ViewSelector = new Lang.Class({
 
         this._searchSettings = new Gio.Settings({ schema: Search.SEARCH_PROVIDERS_SCHEMA });
         this._searchSettings.connect('changed::disabled', Lang.bind(this, this._reloadRemoteProviders));
+        this._searchSettings.connect('changed::sort-order', Lang.bind(this, this._reloadRemoteProviders));
 
         // Default search providers
         // Wanda comes obviously first