Button & keyboard backlight brightness adjustment (1/2)

PS2: move from display to button settings
PS3: fix tab

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: I35a6d149affc1da08707b7c40fb02761321cba41
Merge branch 'cm-10.2' of git://github.com/CyanogenMod/android_packages_apps_Settings into cm-10.2