Datapad / controller navigation

[davebalmer]

Need to sort out a scheme which lets a end user navigate through a UI purely with a D-pad type device. This feature is more for edge case platforms, like games on devices which support a controller (e.g. OUYA, BlackBerry), or smart TV's (and other appliance things).

• navigate between UI items
• respond to typical controls (up, down, left, right, select, cancel, menu)
• ideally should be automatic
• allow developers to provide hinting to the system to make it more to their liking