Navbar settings: add alternate key layout for IME presence

Switches to an alternate key layout when the keyboard is present. also
makes some nice improvements to the loop adding the soft keys and adds a
nested runnable class to be used when i add alternate key layout containers

back, IME switcher, blank space (tablets only), left, up, down, right

todo:  add custom dialog in settings to allow adding/removing
home and ime softkey.  this will happen before alternate key layouts is
added.

Change-Id: I561ca7afaf7c6197a3664ed3f07b1d7097fe0515
Merge "Navbar settings: add alternate key layout for IME presence" into kk44