gold theft while mounted (trunk only)

gold theft while mounted (trunk only)

     From a bug report, "The leprechuan quickly snatches some
gold from between your feet!" doesn't make much sense when you're riding.
Fix started out simple, but "between" isn't right if you're above the floor,
and "rear hooves" for horse or "rear claws" for dragon didn't sound right
for steed (or poly'd hero), so it got a little more complex.  Complicated
even more due to requiring two copies; ick.

     A minor side-effect of this change is that somewhat naughty sounding
"The leprechaun quickly snatches some gold from between your rear regions!"
won't occur anymore.  :-}