title: Animating CAShapeLayer size change
body: <p>I am drawing a circle, with an initial radius of 200</p>
  
  <pre><code>self.circle = [CAShapeLayer layer];
  self.circle.fillColor = nil;
  self.circle.strokeColor = [UIColor blackColor].CGColor;
  self.circle.lineWidth = 7;
  self.circle.bounds = CGRectMake(0, 0, 2 * radius, 2 * radius);
  self.circle.path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(self.radius, self.radius)
  </code></pre>
  
  <p>Can anyone please tell me how to animate a change to a radius of 100?</p>