THIS PLUGIN IS DEPRECATED!!! Plugins should use framework tags instead.
E.g.: <framework src="proxy.php?url=https%3A%2F%2Fgithub.com%2Fcom.google.android.gms%3Aplay-services-plus%3A%2B" /> <framework src="proxy.php?url=https%3A%2F%2Fgithub.com%2Fcom.google.android.gms%3Aplay-services-identity%3A%2B" />>
Full list available: http://developer.android.com/google/play-services/setup.html