Update the GPS tile to use the appropriate location modes

With 4.4, there were new location modes this tile did not support
Update it to turn the GPS on/off without changing the network-based location
option, and use a new icon for battery saving mode.

The tile will now either toggle between high accuracy and battery saving,
or location off and device sensors only.

Change-Id: Ifdfb9832c77671ab1f0c415ea2c25dfee2888578

Conflicts:
	packages/SystemUI/res/values/cm_strings.xml
	packages/SystemUI/src/com/android/systemui/quicksettings/GPSTile.java