title: Swift: Core Animation not animating
body: <p>I'm a noobie when it comes to Core Animation. I'm trying to implement simple animation where <code>UILabel</code> moves from point A to point B. I have the following code that I got from an animation code example but I can't get this to work. The label simply doesnt move. What am I doing wrong?</p>
  
  <pre><code>let frame = self.view.frame
  let blueBox = UIView(frame: frame)
  blueBox.backgroundColor = UIColor(red:  46/255, green: 83/255, blue: 160/255, alpha: 1.0)
  
  let label = UILabel(frame: CGRect(x: 0, y: 0, width: 300, height: 400))
  label.center = CGPoint(x: frame.size.width/2, y: frame.size.height/2)
  label.textAlignment = .center
  label.lineBreakMode = .byWordWrapping
  label.numberOfLines = 0
  
  label.layer.position = label.center
  
  var attrsA = [NSFontAttributeName: UIFont(name: "LemonMilk", size: 92), NSForegroundColorAttributeName: UIColor.white]
  var a = NSMutableAttributedString(string:"Hello\n", attributes:attrsA)
  var attrsB =  [NSFontAttributeName: UIFont(name: "LemonMilk", size: 38), NSForegroundColorAttributeName: UIColor.white]
  var b = NSAttributedString(string:"World", attributes:attrsB)
  a.append(b)
  
  
  label.attributedText = a
  
  let theAnimation = CABasicAnimation(keyPath: "position");
  theAnimation.fromValue = [NSValue(cgPoint: CGPoint(x: screenWidth/2, y: screenHeight/2))]
  theAnimation.toValue = [NSValue(cgPoint: CGPoint(x: 100.0, y: 100.0))]
  theAnimation.duration = 3.0;
  theAnimation.autoreverses = false //true - reverses into the initial value either smoothly or not
  theAnimation.repeatCount = 2
  
  blueBox.addSubview(label)
  
  view.addSubview(blueBox)
  label.layer.add(theAnimation, forKey: "animatePosition");
  </code></pre>