title: How to use Swift Selector? Selector constantly results to `Type has no member`
body: <p>I'm struggling with the following piece of code:</p>
  
  <pre><code>backgroundTimer = NSTimer.scheduledTimerWithTimeInterval(3, target: gvc, selector: #selector(GameViewController.addNext), userInfo: nil, repeats: true)
  </code></pre>
  
  <p>I can't seem to get the #selector working. This code results to:</p>
  
  <pre><code>Type 'GameViewController' has no member 'addNext'
  </code></pre>
  
  <p>Even though the member is right there... Here's the full code:</p>
  
  <pre><code>class GameViewController: GAITrackedViewController, AVAudioPlayerDelegate  {
  
      var sceneCanvas: SKSpriteNode?
      override func viewDidLoad() {
         skView.presentScene(WelcomeScene(size: view.bounds.size, gvc: self))
      }
  
      func createBackground(boundsSize: CGRect, gvc: GameViewController) -&gt; SKSpriteNode {
         addUILabels(gvc)
         return sceneCanvas!
      }
  
      func addUILabels(gvc: GameViewController) {
          backgroundTimer = NSTimer.scheduledTimerWithTimeInterval(3, target: gvc, selector: #selector(GameViewController.addNext), userInfo: nil, repeats: true)
      }
  
      public func addNext() {
          let backgroundLabel = SKSpriteNode(imageNamed: "label1.png")
          sceneCanvas!.addChild(backgroundLabel!)
          backgroundLabel?.runAction(SKAction.moveByX(-screenSize.width , y: 0, duration: 12))
      }
  }
  
  class WelcomeScene: SKScene {
        init(size: CGSize, gvc: GameViewController){
          super.init ()
          let bounds = CGRect(origin: CGPoint(x: 0,y: 0), size: size)
          sceneCanvas = createBackground(bounds, gvc: gvc)
          self.addChild(sceneCanvas!)
      }
  }
  </code></pre>