Add tvOS Focus Engine Support

[FullstackJack]

Currently, the carousel does not focus or handle swipes when presented in a tvOS app.

Expected Behavior: The entire carousel should receive focus. When a user swipes right or left on their remote, the slides should advance forward or backward. Arrows should not be touchable. Bullets should not be touchable.

This may require the main container to be a Touchable and we may need to register a TVEventHandler when focused.

[FullstackJack]

The latest docs show how to register focus and blur event handlers as well as listening for remote events using the TVEventHandler class. http://facebook.github.io/react-native/releases/next/docs/building-for-apple-tv.html