Fix 6683092: tune GlowPadView wave animation

This adds some aesthetic changes to the wave animation for GlowPadView:
- wave shape is no longer symmetric
- disable expand in keyguard
- enable expand in SearchPanelView (when mAlwaysTrackFinger == true)
- if a current wave animation isn't finished yet, don't start a new one
- various timing changes

Change-Id: Ibce96f45eb6a94582c694108b99e243fd57b1955