title: Set tabBarItem.badgeValue for not-yet-alloced viewController?
body: <p>I have used the Tab Bar Application in New Project in Xcode. In IB, I have added NavigationControllers and I have five in total. On app launch the user login, and I would like to set a badgeValue for the fifth tabBarItem, but I am unable to do so, pretty much anywhere.</p>
  
  <p>I'd prefer to do it after the login code has run, but I am not sure how I tell the fifth viewController to get the badgeValue. Also, I have tried it inside the viewController but self.tabBarItem.badgeValue doesn't work either.</p>