Feature android touch updates

This lets you use the onScroll listener of android to detect scroll events in the horizontal or vertical direction.  Also passes down the velocity from the onFling event.  These functions are really useful for touch based camera movements. 
But then, the old one should call the new one, internally. Otherwise we can't ever phase out the old one as the new one depends on its implementation. Also, the two declarations should still be grouped together for clarity (but that's a nitpick/style issue).