Settings: : add ability to change the color in battery saver mode (1/2)

User complain about the ugly orange....give the user the ability to change the
color in status and navigation bar if battery saver mode is activated.

Especially for you Tylog :D

Change-Id: I37bc2865e6af4ea84cb4b9d254f5e8b1580083a9

Conflicts:
	res/values/slim_strings.xml