AE safety issues fixed

Qorbane and Shalbane are now using Radius Enchantment safety code, as
old-style AEs similar to AMA, Winds, etc. This means they're now useable
in all conditions. They will apply to both guildmates and enemies. They
are both also now in a "Bane" subclass that will allow us to easily add
banes for any school if we need to.

Silence has been converted to RE with a 1 mana per second drain. It no
longer breaks Jala songs or prevents all casting. For the time being,
it only prevents communication in a large range around the caster. We
can't have a level 3 spell like this nuking all magic... if someone
thinks of a good use for it, that can be added later.

For now, it still remains unique in that it silences communications.
Perhaps enterprising fighters will use it to prevent calls for help from
victims.