Used to listen for all notifications on iOS.

Listen for all notifications iOS-Swift

NSNotificationCenter.defaultCenter().addObserverForName(nil, object: nil, queue: nil) { (notification) in
    NSLog("Notification found with:\r\n     name:     \(notification.name)\r\n     object:   \(notification.object)\r\n     userInfo: \(notification.userInfo)")
}