fix sleeping shopkeeper's gold handling

fix sleeping shopkeeper's gold handling

     Make a sleeping or paralyzed shopkeeper wake up if you drop something
he's interested in buying (covers the recently reported case where dropping
gold failed to add credit, but picking it back up increased shop dept) or
if you use the 'p'ay command while owing money.  Sleeping shopkeeper is not
affected if you drop something he doesn't care about, or use 'p'ay when
there is no debt, or pick up shop goods (latter case is handled normally--
you'll owe money for the item even though the shk remains asleep).

     This makes shopping become a little easier--you aren't stuck waiting
for the shopkeeper to wake up if you actually want to pay for something--
in the rare case where the shopkeeper has been put to sleep, but it's an
awful lot simpler than any other reasonable way I could think of to deal
with the [lack of] credit problem.

     This makes the snoring message handling moot--it no longer exists.
(It wasn't very reasonable to begin with, because the program can't tell
whether mon->mfrozen is for timed sleep or timed paralysis so avoided
giving that message for temporary sleep.  There ought to be two separate
counters; probing is another case where vague messages are given because
the program can't tell the reason why a monster can't move.)