title: UIScrollViewDelegate. scrollViewDidScroll not getting invoked (Swift/Interface Builder/Xcode 6)
body: <p>I'm trying to hook up a scroll view using Interface Builder, and the <code>UIScrollViewDelegate.scrollViewDidScroll</code> method isn't getting invoked on scroll.</p>
  
  <p>In IB, I have a view controller that uses my <code>PagedScrollViewController</code> as a custom class.  In that class, I have:</p>
  
  <pre><code>class PagedScrollViewController: UIViewController, UIScrollViewDelegate {
      func scrollViewDidScroll(scrollView: UIScrollView!) {
          println("scrollViewDidScroll")
      }
  }
  </code></pre>
  
  <p>Unfortunately, that <code>println</code> is never getting invoked.  I know that <code>PagedScrollViewController</code> is being connected correctly because if I add a <code>viewDidLoad</code> method, that gets invoked.  Is there something extra I need to do to attach the delegate other than setting the custom class?</p>