title: Error with SKAction.runBlock
body: <p>Here is some simple code from a SpriteKit test app I'm playing with:</p>
  
  <pre><code>let wait = SKAction.waitForDuration(1)
  let perform = SKAction.runBlock({self.checkAnswer()})
  let checkAnswerSeq = SKAction.sequence([wait, perform])
  </code></pre>
  
  <p>I'm getting a "'SKAction' is not convertible to '(Selector, onTarget: AnyObject!) -> SKAction!'" error on the second line. Any ideas?</p>