Fixed bugs related to flick trajectory and boundary collision.

1. Deceleration after flicking is now applied based on angle, instead of
equally to x and y components, preserving trajectory.

2. Image does not come to full stop when flicking into a boundary if it can
still travel in one component of the velocity.
Change-Id: I36cea8a0d2fc13e7bb20e43599f4a2ae064005d3
Merge "Fixed bugs related to flick trajectory and boundary collision."