SystemUI : Make battery percentage configurable

Change-Id: Ibfc0cf9c5a4efc13ecd3c3e99723bb2b717c50a7
Battery text mode (1/2)

PS2: Make battery level more fit current solution
PS3: Fix displaing battery level inside the icon
PS6: Show battery level in status bar header when charging and percentage
     mode set to inside icon (it's replaced by charging icon)

Change-Id: I537c99827e78c796b4980ec7751e5f9b58a88251
Signed-off-by: kecinzer <kecinzer@gmail.com>

Conflicts:
	core/java/android/provider/Settings.java
	packages/SystemUI/src/com/android/systemui/BatteryMeterView.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBarHeaderView.java