TC-4654 : iOS 8 : Add isRegisteredForRemoteNotifications to determine if Registered for Notifications

Add support for isRegisteredForRemoteNotifications so that the developer can check if the user has authorized notifications.

var hasAuthorized = Ti.App.iOS.isRegisteredForRemoteNotifications();
if(hasAuthorized){
	Ti.API.info("User has already authorized");
}else{
	Ti.API.info("User needs to authorize, maybe ask them before the iOS rights dialog pops up");
}