rc.shutdown :
Added ask_to_save_function because a few forum
members are fond of such. Latest diff by SFR, but
code snips had been around for a few years by
several forum members. Reworked his diff into a function
to be used by PUPMODES 3 7 13 .
http://murga-linux.com/puppy/viewtopic.php?p=737246#737246