Add onStylusButtonPress listener to View

The gesture is: stylus touching screen + button pressed, the event
is recognized when the button is pressed, not when it's released.
It can be pressed during DOWN or MOVE.

If the stylus touch + press button is occurring longpress cannot
occur and vice versa. Also adds the haptic feedback and accessibility
bits specific to the new gesture.

Bug: 19620479
Change-Id: Ibc4654978ef39e7b4251d17636453d90f3bf622d