Mob Mask

New Features:
- every 300 killed mob or player will drop a head on the entire
server now is not a probability number it will drop every 300 killed
mob or zombie this number increments by all the players on server
so if 1 player kill 100 and other kill 199 the next player that kills a player
or mob will receive their head

- now looting increments the drop rate looting one increment 1 and looting 3 increments 3
so you have to kill 100 mobs with looting 3 to receive their head

- added compatibility to 1.8

- added a broadcast message to all players when a player decapitate another player or mob

To-Do:
a configuration file to set the value of drop which is 300 right now
add other mobs heads