[3017] Implement script support for the Headless Horseman - Hallow's End boss

Conflicts:
	scripts/eastern_kingdoms/scarlet_monastery/boss_headless_horseman.cpp
[3018] Implement NpcSpellClick script hook. Requires CMaNGOS 12674+

Conflicts:
	ScriptMgr.h
	sql/scriptdev2_script_full.sql
[3019] Implement script support for quests 11476 and 12075

Close #110

Conflicts:
	scripts/northrend/dragonblight.cpp
[3020] Fix typo

Close #109

Conflicts:
	scripts/northrend/ulduar/ulduar/ulduar.h
[3021] Fix script for quests 1222 and 1270

Thanks to @grz3s for providing the proper data

Close #86