Allow Powerdown menu for devices other than M1

Just because device can't power itself off, doesn't mean system shouldn't be given opportuntity to have a clean exit from xbmc.

This renables Powerdown menu so S95-xbmc script has a chance to run and dismount drives and removable media.

On M3 users will have to physically remove power to power off.
Merge pull request #7 from toys4me/PR/SafeShutdown

Allow Powerdown menu for devices other than M1