container groundwork

container groundwork

     Move a couple of instances of container contents manipulation into
their own routines.  Behavior for items disappearing from cursed bags of
holding isn't quite identical but is effectively the same.  I think its
use of stolen_value (or simply the behavior of the latter) is buggy, but
I haven't tried to fix that.  (Cursed bag of holding destroying a player
owned bag containing shopped owned items definitely doesn't work well.)