Add fast track window animations.

The enter animation works; the exit animation doesn't, because of the
associated with the activity.  In theory I have a dummy animation
also associated with the activity to keep it around during the exit
animation, but this isn't working and I need to figure out why.

Change-Id: I1a3a3e4832e62080c35b4bc8f888bdc2d90528c8
8 files changed