Mob Mask

New Features:
- Fix way of handle damage from monsters now they will not follow you
and creepers wont explode near you thanks to IngrounPenguin
- Fix display name on heads now is named as the mob Pigman Head, Pig Head, etc.
- Fix Reset name when breaking a mob head now it keep the name as Pig Head etc...
- Add deathmsg on config.yml that allows server admins to customize the death message
when a player or mob is decapetated.

To-Do:
- add a command to get heads of players
(if found a skin with a mob that is not listed here please share)
- add heads for zombie and skeleton horses.