title: Adding back button to navigation bar
body: <p>I've added a navigation bar to a UIViewController.  It is displayed from another UIViewController only.  I'd like to have a left side back button that is shaped similar to an arrow, just like the normal navigation bar back button.  It seems I can only add a bar button through IB.  I'm guessing the back button needs to be added programmatically.  Any suggestions on how I should do this?</p>
  
  <p>Currently, in the RootController, I push another UIViewController (viewB) by simply doing an addSubView.  In viewB, I want to display the navigation bar.  The app is view based, not navigation controller based.</p>