Battery level: customizable icon and text

Squashed commits from Slimsaber (original code by @kecinzer)
This also revert the native android battery in-icon percentage
commit.

Change-Id: Idcec37dad02bc93429abcde38f05b152c3bea005

Conflicts:
	packages/SystemUI/res/layout/status_bar.xml
	packages/SystemUI/src/com/android/systemui/BatteryLevelTextView.java
	packages/SystemUI/src/com/android/systemui/BatteryMeterView.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java