Settings: Add Advanced reboot (1 of 2)

This commit adds a setting in Development settings for including options
in the power menu for rebooting into recovery or bootloader, defauled to
off.

When enabled, the Advanced reboot options will only be available once the
device is unlocked.

Change-Id: I72d6df55bf5df251802b321410670646d26c54b0
Merge remote branch 'cm/cm-10.1'