title: Pull to refresh in UICollectionView in ViewController
body: <p>I used the following code at a <code>UICollectionViewController</code></p>
  
  <pre><code>override func viewDidLoad() {            
  
      self.collectionView!.alwaysBounceVertical = true
      let refresher = UIRefreshControl()
      refresher.addTarget(self, action: "refreshStream", forControlEvents: .ValueChanged)
  
      refreshControl = refresher
      collectionView!.addSubview(refreshControl!)
  }
  
  func refreshStream() {
  
      print("refresh")
      self.collectionView?.reloadData()
  
      refreshControl?.endRefreshing()
  
  }
  </code></pre>
  
  <p>Now I need it to work with a <code>UICollectionView</code> inside a <code>UIViewController</code> and I googled for an hour now but can't get it working.
  I appreciate any help.</p>