Elastic Animated Check Box inspired by https://dribbble.com/shots/1631598-On-Off and http://robb.is/working-on/a-hamburger-button-transition/
pod 'TKAnimatedCheckButton'
self.button = TKAnimatedCheckButton(frame: CGRectMake(0, 0, 44, 44))func toggle() {
self.button.checked = !self.button.checked
}self.button.color = UIColor.redColor().CGColor
self.button.skeletonColor = UIColor.blueColor().CGColor