Use a common base class for HW tuning sliders.

Change-Id: I61b458ffb08eb765f8a720657056243f56e76f17

Conflicts:
	src/com/crom/settings/fragments/ButtonBacklightBrightness.java
	src/com/crom/settings/fragments/KeyboardBacklightBrightness.java
	src/com/crom/settings/fragments/VibratorIntensity.java