power menu: reboot and screenshot

Ported from CyanogenMod 10 mr1-staging branch
https://github.com/CyanogenMod/android_frameworks_base/tree/mr1-staging
Framework: Forward port Expanded desktop capability

Originally authored by Jesús David and ported from
        ParanoidAndroid ICS branch for CyanogenMod 10
Contributors:  Rework Done by Dan Synmonds, Paul Beeler, David van Tonder and Rascarlos

Signed-off-by: Paul Beeler <sparksco@gmail.com>