title: Hide keyboard on touch anywhere outside UITextField when view includes UICollectionView
body: <p>There are some answers out there such as <a href="https://stackoverflow.com/questions/4941332/how-can-i-dismiss-keyboard-when-i-will-just-touch-anywhere-except-uitextfield">this</a>, but in the case where there is a <code>UIScrollView</code> or <code>UICollectionView</code> present, it doesn't work.<br>
  The <code>touchesBegan</code> method on the <code>viewController</code> will never get called.</p>
  
  <p>On screen, I have a <code>UITextField</code> at the top.<br>
  Below that, filling up the rest of the screen is a <code>UICollectionView</code>.<br>
  I need to dismiss the keyboard if I touch anywhere besides the <code>UITextField</code> (<em>including the collection view obviously</em>)</p>
  
  <p>So what is the best way to do this?  </p>
  
  <p>For such a common UI paradigm it seems like there should be a well-known solution, but I've yet to come across it.</p>