LastApp Toggle [1/2]

Creates an action useable by NavBar & NavRing to toggle
between most recent apps.  Will try to ignore the launcher
when possible.  ie, if you've just rebooted and have not opened any
apps, it will do nothing.  if you open 1 app, it will toggle between
that 1 app and the launcher.  Once two apps have been opened, it will
toggle between those two apps.
It's kind of like opening recents and hitting your #2 slot repeatedly

PS 2:  Add Icons from Hoolm.  {Thanks!}
       Re-wrote the logic for selecting next app.  Rather than
toggling back to launcher if only 1 app open, it does nothing.
toggling only occurs now when there are at least two apps open.
One issue that I still need to work out is that 'Recents' is somehow
showing up as a valid target to toggle to.  It shouldn't.

ps 3:  getRunningTasks() does not filter out 'Excludefromrecents'.
Thus we need checks for 'default launcher' and SystemUI.
as I write this, I realize I might be able to query the
ExcludeFromRecents flag of the package a bit more easily.

ps 4: Whitespace fix.
ps 5: one more whitespace fix.
ps 6: remove unnecessary dependency

Signed-off-by: Zaphod <mwilson@acesappraisal.com>
Change-Id: I0b59121b07b9ba44a2837a8db0266441ed82f9a3
Merge "LastApp Toggle [1/2]" into jb-mr1