Radius enchantment structure

* 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.

* This fixes death bugs and the engine bug where jumping puzzles were impossible
with a radius enchantment up because of constant z updating.

* 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). For example, an item can be made that casts Umbrella when
dropped on the ground. Or, an NPC could sing Rejuvenate for a fee.

* 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 direct interaction). Mana
Convergence was simply countering AMA completely, which overly hindered
the Anti-Magic playstyle. This should be a good balance and use for MC.
Full reasoning found here:
http://openmeridian.org/issues-to-be-tackled-1-pfs-vs-pms/

* 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
a situation I really expect to see in PvP, but will be very dangerous when
Sandstorm is employed by certain new PvE enemies. Sandstorm does not
do damage or vigor loss to any player inside a guild hall, regardless of
the location or affiliation of the source.

* 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).