I/O scheduler settings

Refs: http://review.cyanogenmod.com/#/c/23532/

This needs a change of permissions of /sys/block/mmcblk0/queue/scheduler
(separate commit project CyanogenMod/android_system_core)

Patch set: translatable="false"

Same as for JB: http://review.cyanogenmod.com/#/c/22127/

Change-Id: Ibb01cecff7712ad654242f616d0ecf99439471d0

Conflicts:
	res/values/strings.xml