Create Pig.java

I made this file using @PEMapModder 's way.
Update EntityType.java in @PEMapModder 's way.
Create Enderman.java
Create Sheep.java
Create Silverfish.java
Create Skeleton.java
Create Creeper.java
Create Mooshroom.java
Create Cow.java
Create Wolf.java
Create Villager.java
Create Zombie.java
Create ZombiePig.java
Create Slime.java
Lol xD
Merge pull request #51 from jose-vm/patch-4

Complete Entities Files