SystemUI: add signal text (1/2) WIP

Change-Id: I0b1a246f4744e71fb6cebfdfe2f674958971048e

SystemUI: replace signal bars with signal text if option chosen

Change-Id: I3b50747031f6e80edcad4499f0ad2646483c94c0

fix airplane mode with SignalText
Took the visibilty checks out of SignalText.java and moved to signalClusterView.
Airplane mode icon now properly responds.

Change-Id: I4e97854a3ed59df26d12b881b73b8f59c75de3db

fix Dbm signal readout for LTE/4g
This uses deprecated methods for getting signal values, but
it is the way it's currently being done in Settings.apk in AOSP.
there is no LTE functionality in the new preferred method.  Until
such time as LTE signals are exposed, this looks to be the only way.

Clean up
I forgot to take out the log statements and delete
commented out code.

Change-Id: I96fe28fdf946e1372ec4dd8df3adae4aece4b509

Conflicts:
	core/java/android/provider/Settings.java