NvaigationBar title replaces TabBarItem item on iOS

ie. if they're different, when you visit the tab, the tab bar item title changes.

this issue is described here http://stackoverflow.com/questions/21615637/how-to-change-uiviewcontroller-title-independent-of-tabbar-item-title

I'm happy to fix this, do you guys have any preference between any of the hacky solutions proposed in that stack overflow link? ;)

No file or test is named in the issue; begin with the linked Stack Overflow discussion and the iOS navigation/tab implementation, then reproduce the shown case with different navigation-bar and tab-bar titles. Done means visiting the tab no longer replaces the TabBarItem title, with a regression check covering that behavior.

Written by the indexing model from the issue text.