Added custom mob head: slime (Thanks Glompalici0us)
Added custom mob heads: squid, silverfish, ender dragon, slime, iron golem, mushroom cow, and bat (Thanks SethBling)
Removed manual iterations of CustomSkullType
Converted old slime to new custom mob head: horse (Thanks Glompalici0us)
Fixed where custom mob heads would drop when destroyed in creative mode
Fixed updated localization