[8658] Threat calculation fixes and improvements.

* Add single arg version Unit::AddThreat for just adding to threat list.
* Req. provide schollmask and crit flag for any real threat value for proper threats mod apply.
* Send crit flag in DealDamage as MELEE_HIT_CRIT for spell damage for later send to threat call.
* For not affected by modifiers threat values use SPELL_SCHOOL_MASK_NONE.
* Implement aura SPELL_AURA_MOD_CRITICAL_THREAT (used only in itemset 529 effect).

src/shared/revision_nr.h

@@ -1,4 +1,4 @@
 #ifndef __REVISION_NR_H__
 #define __REVISION_NR_H__
- #define REVISION_NR "8657"
+ #define REVISION_NR "8658"
 #endif // __REVISION_NR_H__