Tap delays; making tap UI feel better.

Addresses bug 2317577

Views now will not enter PRESSED state until
ViewConfiguration.getTapTimeout() milliseconds have elapsed. This
prevents scrolls and other gestures from causing views to enter
PRESSED state prematurely.

Quick taps within the same view still work as expected. There is now a
PREPRESSED state flag within View to help track quick taps.

If tapped quickly, views will remain pressed for
ViewConfiguration.getPressedStateDuration().

Tap timeout has been changed to 115ms. Pressed state duration has been
changed to 125ms.