title: How to hide Bar Button Items when UITableView is in edit mode? (Swift)
body: <p>Title essentially says it all. </p>
  
  <p>I have a <code>UITableView</code> and I want the <code>RightBarButtonItem</code> item to disappear while the <code>UITableView</code> is in edit mode. Unfortunately, all of the answers that I have found so far suggest setting the button to nil... which won't work for me because I do not want to get rid of the button and the reference to it, just hide it while the <code>UITableView</code> is in edit mode. </p>
  
  <p>What I'm having trouble figuring out what to do, then, is:</p>
  
  <ol>
  <li>Detect when the <code>UITableView</code> has entered editing mode</li>
  <li>Hiding the <code>RightBarButtonItem</code> (not removing it entirely) </li>
  <li>Detect when the <code>UITableView</code> has left editing mode (so the button can reappear)</li>
  </ol>
  
  <p>Any help would be appreciated, thank you!</p>