registerForRemoteNotifications method should be invoked on Main Thread

[bioffe01]

https://github.com/ashishkakkad8/Notifications10ObjC/blob/f83482ff3b0d42a206bd79bfdaccf8cdaff4f73b/Notifications10ObjC/AppDelegate.m#L104

[darkstarx]

Use this

	dispatch_async(dispatch_get_main_queue(), ^{
		[[UIApplication sharedApplication] registerForRemoteNotifications];
	});