[3017] Implement script support for the Headless Horseman - Hallow's End boss
[3018] Implement NpcSpellClick script hook. Requires CMaNGOS 12674+
[3019] Implement script support for quests 11476 and 12075

Close #110
[3020] Fix typo

Close #109
[3021] Fix script for quests 1222 and 1270

Thanks to @grz3s for providing the proper data

Close #86