Core/Account: Move AccountMgr back to singleton
DB/Misc: Proper faction for npc Brann Bronzebeard.

This makes him assist in combat and now the mobs that spawn attack him.
Script/Scholomance: Update Kirtonos the Herald script.
DB/creature: Add some missing Zul'Gurub Panther Trigger spawns
Core/Misc: Delete spell from character_spell table too when encountering an invalid spell