Radius Enchantment System Upgrade

* Each Radius Enchantment spell now keeps track of all its own
instances. Nothing goes through a player's data that is critical for
spell functions.

* All nomoveons and items now have plRadiusEnchantments lists. Monsters,
players, and items can all be affected by radius enchantments (or be the
source of one).

* Mana Convergence now only affects Attack spells. This includes Riija's
Illusionary Wounds and Qor's Splash of Acid & Vampiric Drain. Bolts also
fall under this category. This is intended to allow mage characters to
fight through AMA (MC and AMA still have no effect on each other). Mana
Convergence was simply countering AMA completely, which overly hindered
the Anti-Magic playstyle. This should be a good balance.

* Invigorate, Restorate, and Rejuvenate now add flat amounts of their
respective secondary stat (up to 1/second at 99 spellpower). This
contrasts with the old system, in which their boosts to regeneration
could often be useless.

* Sandstorm deals up to 4 damage and 4 vigor loss per 3 seconds, based
on spellpower. If a player drops below 10 vigor, Sandstorm will stop
draining their vigor, but do triple damage instead (because they're
exhausted and can no longer fight the winds & sand). This is not
something I really expect to see in PvP, but will be very dangerous when
Sandstorm is employed by certain new PvE enemies.

* Jala spells don't require a lute to cast anymore, but your spellpower
will suck. It's still recommended to start a song using a lute (song
power cannot be later improved once casting has begun).