Add back backlight curve adjustment.

Patch set 1-8: Initial commits
Patch set 9  : Shortened strings to better fit Design Guidelines

Change-Id: I1eb370f8911d1c92ef06e553cc1c1be81e83cb95

Conflicts:
	res/values/strings.xml

Signed-off-by: Paul Beeler <sparksco@gmail.com>
Some post-merge cleanup for automatic brightness adjustment

- Remove some unused strings
- Use (device-dependant) minimum brightness level (as calculated by
  DisplayPowerController) as '0%' instead of the actual value 0.

Change-Id: I79123d2421c9ab35fa0f1808d82d785463e8fbaa
Settings: fix incorrect value in autobrightness adjustment

If the user drag the progress bar below the min value, the incorrect
setting will be saved since seekBar.setProgress code path does not
return to the "getItem(pos).backlight = ..." line.

Change-Id: I4796e22ba9c44315be92de4040f6cd8451bdf153