Messing up wog immunity checks

0x75B4CA is the function for casting Sorceresses' spells and stack exp spells.
There are issues here:
- Spell immunity checks aren't universal

As we see from the screenshot (0x75C01B), it uses creature IDs for spell immunity checks. This means the native spell immunity mechanism is ignored, which brings different problems:


For Age set with Stack Exp Ability after attack
a. Setting immunity to Age with MR:F100 under !?MR2 doesn't work
b. level 1-5 Spell immunity granted from stack exp ability doesn't give immunity to Age
c. Setting a non-living flag on a creature doesn't grant it immunity to Age
d. Dwarf-type spell immunity (from the creature itself or secondary skills) doesn't help reduce the chance of Age, while it should (See 0x44029B)

Suggestion: I think it should use the same way after-hit spells are implemented in the original H3 (0x440220) for spell immunity checks.

- Duplicated spell casts
Many creatures with after-hit spells in the original H3 grant the same spell cast from stack exp, for example, War Unicorns (Blind) and Ghost Dragons (Age).
There isn't a check for the existing debuff of the attacked stack, thus this can happen:
After Unicorns attack their enemy, they cast Blind twice (one from their ability, one from stack exp), which is visually unpleasant and sometimes makes things worse (if the new spell is worse than the existing one)

Suggestion: There should be an existing spell check inside 0075B4CA before applying a new spell.
Say, if the attacked creature has possessed a Level 0, 3 turns Blind Spell (can be cast by a unicorn with no exp), when the new spell is the same type (Blind) and both level and power are no greater than the existing spell, it should not be cast.
More specifically:
Existing spell on the hostile stack: level 0, duration 3 Blind, if the new spell to be cast is
Level 2, duration 1 Blind - can be cast, overrides the current spell
Level 0, duration 6 Blind - can be cast, extends the duration of the current spell
Level 0, duration 1 Blind - can't be cast as it is no better than the current possessed spell in any aspect