Framework: Add option to always show battery status on lockscreen (1/2)

Based on the feature by burnsra in CM7
Authored by Blunden
Tweaked by DvTonder
Change-Id: I642da4dcd82a776a74d77031d37acc76f97b25af

lockscreen battery status: add off option (2/2)
Change-Id: Ie10015865f161e783dc394d467e456d51dc9fbbc

Conflicts:
	core/java/android/provider/Settings.java
	core/res/res/values/symbols.xml