searchDisplay, and others: Switch from provider title to provider icon

Display a '+' icon on the provider icon if there are more results that are
hidden. If the provider icon is clicked, ask the provider to launch itself and
perform a search with the current terms.

https://bugzilla.gnome.org/show_bug.cgi?id=681797

js/ui/remoteSearch.js

@@ -176,7 +176,7 @@ const RemoteSearchProvider = new Lang.Class({
         this.proxy = new proxyType(Gio.DBus.session,
                 dbusName, dbusPath, Lang.bind(this, this._onProxyConstructed));
 
-        this.parent(appInfo.get_name().toUpperCase(), appInfo, true);
+        this.parent(appInfo, true);
         this._cancellable = new Gio.Cancellable();
     },