Enable Safe shutdown and reboot w/Splash screens

This should help eliminate disk corruption if proper menu items for shutdown and reboot are used.

Modified S95xbmc script to shutdown disks, flush information, etc before reboots or power down.

Added some splash screens to better keep user informed about what is going
on at boot/shutdown and to let them know when safe to turn off device.

Note: for this patch to have benefit to M3, xbmc must be modified so shutdown = true for the M3.