Implemented broad support for fields min_dist, min_dist_mod, max_dist, max_dist_mod -

Scales spell power based on targets distance from caster.
This implemented in a broad way to function with spells
that would make sense to scale. Some work will still be needed on this.

Be aware if making custom
spells not everything will work and certain effects just
should not be included (use common sense).

common/spdat.cpp

@@ -1040,6 +1040,15 @@ bool IsCastonFadeDurationSpell(uint16 spell_id)
 	return false;
 }
 
+bool IsPowerDistModSpell(uint16 spell_id)
+{
+	if (IsValidSpell(spell_id) && 
+		(spells[spell_id].max_dist_mod || spells[spell_id].min_dist_mod) && spells[spell_id].max_dist > spells[spell_id].min_dist)
+		return true;
+
+	return false;
+}
+
 uint32 GetPartialMeleeRuneReduction(uint32 spell_id)
 {
 	for (int i = 0; i < EFFECT_COUNT; ++i)