overlay: add soft reboot

Change-Id: If5ccb3194126f8670acfd7235cae05dfb7e1ecfa
fstab: support f2fs-formatted data and cache

!! IMPORTANT !!
This patch requires two patches that, as of 8/29/14, are
not merged into mainline cm:
http://review.cyanogenmod.org/#/c/65480/
http://review.cyanogenmod.org/#/c/68737/

(68737 could have been handled here, but its cleaner in vendor/cm)

Change-Id: Ic9a33c7aaa20728cf53b7aae1736f52d52c5a31f