Fix number item issue with buyer NPCs

The intermediary numberitem stack wasn't being deleted if the NPC
already had a stack of that item, and for rainbow ferns this was causing
dangling timer issues. These are now deleted properly.
NPC speech library fixes
Changes from original repo

monster.kod Buy() now handles mobs that sell from inventory (Izzio,
Pacal).
Bonk fixes

No more bonking blind/dazzled players to allow them to see under some
circumstances.
Bonk can also be cast by non-DMs, for the rare occasions where a monster
or player will have the ability to cast this.
Merge branch 'npctextfixes' of https://github.com/skittles1/Meridian59_103 into build.1.0.411-req.694-br.npctextfixes-auth.skittles1