Fix 4689527: Improved curation for Recents + misc cleanup

This sets a threshhold for both the curation animation as well as the
snap back animation.  It now limits these to 500ms and 250ms, respectively.

Cleaned up misc log spew.

Updated after review.

Change-Id: Ie11a2fc4556b396257c33c3ebd7513c4c220ff95