void on_remove(object ob)

Called to inform you that ob has been removed from this_object(). It is
called after the object has already been moved, and is intended to allow
you to recalculate weights/bonuses/etc.

int on_remove()

This is called when THIS object is removed (i.e. it is clothing and
this_player() has taken it off). It does not imply object movement. If
you need to listen to both events, this is equivalent to passing in
an ob of 0.

If you return 0, the default removal behavior (setting worn to 0 and
printing a message) will occur. If you return 1, then nothing further
will happen -- this lets you implement cursed unremovable items, or
destroy the object, for example.
