Rotating a UIButton by 90 degrees every time the button is clicked
<p>How do you rotate a UIButton by 90 degrees each time the button is clicked and also keep track of each rotated position/angle?</p>

<p>Here is the code I have so far but it only rotates once:</p>

<pre><code>@IBAction func gameButton(sender: AnyObject) {
    UIView.animateWithDuration(0.05, animations: ({
        self.gameButtonLabel.transform = CGAffineTransformMakeRotation(CGFloat(M_PI_2))
    }))
}
</code></pre>