Enhanced VelocityTracker for > 5 pointers and fixed bugs.

Improved PointerLocation tool to use VelocityTracker more efficiently
and correctly when multiple pointers are down.

Fixed a bug in TouchInputMapper where it was not correctly copying
the id to index map in the last touch data.  This could cause strange
behavior on secondary pointer up events.

Also added finished callback pooling in InputQueue.

Change-Id: Ia85e52ac2fb7350960ea1d7edfbe81a1b3e8267b