Check for spell cast by item in shal/qorbane.

Some items currently do cause damage, some don't, and some throw lots of
errors. For now, all items don't cause damage (or throw errors).
Misc error fixes.

-Stop reflections and ETs throwing errors when trying to call GetName
after deleted (post delete).
-Stop trying to place spider webs on $ row/col (possibly called after
user has logged off or otherwise messed up the cast).
-Check for Battler class in Monster.IsAlly, to stop monsters trying to
ally with items or spells.