title: Recognize tap on navigation bar title
body: <p>Could someone please help me recognise a tap when a user taps on the <strong>Title</strong> in the <strong>Navigation Bar</strong>?</p>
  <p>I would like to recognise this tap and then animate the <strong>tableHeaderView</strong> appearing. Possibly sliding the TableView down.</p>
  <p>The idea being that the user can then select a quick option (from the tableViewHeader) to re-populate the TableView.</p>
  <p>However I cannot recognise any taps. I'm using Swift.</p>