[TIMOB-9929] TiAPI: Reconcile UI.Button's background color qualities, especially in context of iOS's UIButton tint.

With iOS 5, we now have the ability to customize aspects of iOS's button (and other views) that we previously have not. But in investigating a pull request, it has become obvious that there is an impedance mismatch with what Titanium exposes as backgroundColor (The color that most of the view is filled with) and what UIButton uses as backgroundColor (The color filling in the unused rectangle of the view) and tintColor (The color used by the button depending on circumstances). Button, plain: Button, in Navigation bar: Button, rounded rectangle: Button, with background image: Button, info Button, in Toolbar: (To be filled in further to show all the edge cases)