Softkeys: Bug fix and preliminary doubletap action support

The ActionHandler overhaul introduced a small bug in which
the home button was not properly handling search panel.
Our default "no action" is no longer "empty" here.

Also clean out unused uris and attributes, mostly
color stuff we don't do.

Change-Id: Ib28cfca0bb43f6f1896d4a404385c8898d5566c0