title: Where to set navigationItem of view controller in navigation stack
body: <p>I have a traditional navigation based app. Should I set the navigation item of the viewcontroller I'm pushing in the view controller it self (eg self.navigationItem ...) Or in the view controller which is about to be popped (eg myViewController.navigationItem ...)?</p>
  
  <p>Also if I should put it in the view controller that's being pushed, should I set up the navigationItem in the init method, or viewDidLoad, or somewhere else?</p>