title: Swift Change ViewController of Current UITabBarController
body: <p>I have a UITabBarController with 3 tabs that have VC1, VC2 and VC3 in each of the tabs respectively.  In VC1 I have a button that when pressed I want to REPLACE the VC1 with VC4.  How do I get the UITabBarController and update the VC array to now be VC4, VC2, VC3.  Can I do that inside of VC1 or do I need to post a notification that the appdelegate handles?</p>