title: Could not instantiate class named IBNSLayoutConstraint
body: <p>I'm using XCode6 beta and trying out Swift. When I put some auto layout constraints in a view controller the app crashes with the following error:
      <code>Terminating app due to uncaught exception 'NSInvalidUnarchiveOperationException', reason: 'Could not instantiate class named IBNSLayoutConstraint'</code></p>