Dement, Enfeeble and Vertigo code changes, Disease consolidated into Debuff, new Deleted class for removed classes.

All three spells function the same as before, but I've taken the code from the Dementia and Palsy classes and consolidated it into Dement and Enfeeble. These two are now in class Disease which is a subclass of Debuff (solely so diseases can still be distinguished from other debuffs) and the Disease class now holds code common to both debuffs. Vertigo now contains a DoSpell function for the actual casting of the spell (so it propagates and displays the duration).

Created a new Deleted class for dangling classes left from deletes such as this one, and moved the deleted wands there too. This seems to remove the templates for them in the game/save game, so they could then be deleted safely at a future date. As far as I know, this is the easiest way to fully delete classes, although I still need to verify that it works on 104.