Attack Spell changes

* JoFs now boost blast and bolt spells by 3 each, instead of boosting
touch spell damage. The extra mana drain remains the same (up to 4 for
double use). This damage is bonus damage, which is added after resist
and vulnerabilities (so no increased damage, but no reduced damage
either). This should allow more consistency for spell attacks against
resistant targets.

* Princess Shields now act as conduits the same as Jewels of Froz. A JoF
+ Princess shield is the same as wielding 2 Jewels. The Princess shield
mana reduction ability remains, helping to compensate for its own attack
spell mana cost boost.

* Duke shields now reduce all spell attacks post-resistances by 6
damage, exactly equal to the double jewel of froz bonus. Duke shielders
will take 6 less final damage from, for example, groundworm acid
attacks, player blasts of fire, and holy enchanted long swords.

* Ivies and robes of the disciple had their gratuitous shock resistance
removed. Ivies are now 20% weak to unholy to match Orc Shields' 20%
weakness to holy.

* Armors other than plate had similar fire and shock weakness added.
Nerudite armor had its fire resist lowered to 10 from 20, and shock
resist lowered to 5 from 20, to continue having 20% advantage over the
other armors. Leather armor is not weak to shock, and its defense has
been boosted from 50 to 200 to help against early touch spell PKs.

* Knight's shield had its 20% weakness to all spells changed to 10%
weakness to fire and 15% weakness to shock, so that its weaknesses stack
with regular armor (and so that resist rings eliminate the weakness).
Not that everyone isn't just using soldier shields anyway.

* Helm had its bludgeon weakness changed to a bludgeon resistance.
Possible typo?

Cold and Acid remain largely orthogonal damage vectors. Holy and Unholy
remain unresisted by anything except a Duke Shield, and weak only in
their respective karma items.