SystemUI: cleaner recents key implementation

Also, I noticed that the RecentsTaskLoader implemented
View.OnTouchListener, so just use that implementation for the button.
Also camelCased some variables.

I can't stand the way AokpTarget looks... so I renamed it to
AwesomeAction :/

Change-Id: If51c592bebcfbe98d49bb362f845a1b1d86cfb1e
Signed-off-by: Roman Birg <romanbirg@gmail.com>