cleanup imports and add "final" declaration & @Override per Eclipse
stop dropgroups sending a blank line to player's chat
minor - avoid issue with tailing characters (eg. DIAMONDSWORD@!)
center mob spawns on the block, rather than spawning in the corner
Eclipse cleanup
allow EXPLOSION_TNT to match EXPLOSION_PRIMED_TNT (which is what actually occurs)
register PigZombieData class and allow it to extend Zombie (to allow for @BABY or VILLAGER pigzombies)
Release 2.8-beta6