title: How to find out if a UIViewController is the root view controller?
body: <p>basically I want to know if the view controller I'm in is the root view controller or not.</p>
  
  <p>If its not I want to put a button in the nav bar that says "back" (as if it were a proper back button - this bit I know how to do).</p>
  
  <p>Before you ask, I have removed all the titles from my view controllers - I didn't want them to show up on my navigation bar... its very complicated - but this means that when I go through my navigation stack none of the pushed view controllers have a back button. :/</p>
  
  <p>Thanks
  Tom</p>