stop occupation during problem countdown

stop occupation during problem countdown

     A user recently complained that he started an activity such as
searching and specified a repeat count, right after getting--and not
realizing the significance of--the first message in the countdown
sequence for turning into stone.  He suggested that subsequent messages
interrupt multi-turn activity so that the player has a chance to do
something to prevent imminent death.  This implements that, with the
added wrinkle that it won't interrupt if the activity is something that
might save the character's life:  attempting to eat a tin that is either
sure to help (if ID'd as food that cures stoning) or a desparate gamble
(if unID'd).  Some hooks for similar behavior for other conditions like
turning into slime are included, although no tins can help for anything
other than petrification so far.

     Shouldn't fatal illness have an end-is-near countdown too?