override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    NSNotificationCenter.defaultCenter().postNotificationName(TOUCH_BEGAN, object: touches)
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
    NSNotificationCenter.defaultCenter().postNotificationName(TOUCH_MOVED, object: touches)
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
    NSNotificationCenter.defaultCenter().postNotificationName(TOUCH_ENDED, object: touches)
}