Adding all Entities into CraftBukkit.

These are needed to properly allow for determining class type, in
accordance with current practice.

src/main/java/net/minecraft/server/EntityCow.java

@@ -0,0 +1,49 @@
+package net.minecraft.server;
+
+public class EntityCow extends EntityAnimals {
+
+    public EntityCow(World world) {
+        super(world);
+        aP = "/mob/cow.png";
+        a(0.9F, 1.3F);
+    }
+
+    public void a(NBTTagCompound nbttagcompound) {
+        super.a(nbttagcompound);
+    }
+
+    public void b(NBTTagCompound nbttagcompound) {
+        super.b(nbttagcompound);
+    }
+
+    protected String e() {
+        return "mob.cow";
+    }
+
+    protected String f() {
+        return "mob.cowhurt";
+    }
+
+    protected String g() {
+        return "mob.cowhurt";
+    }
+
+    protected float i() {
+        return 0.4F;
+    }
+
+    protected int h() {
+        return Item.aD.ba;
+    }
+
+    public boolean a(EntityPlayer entityplayer) {
+        ItemStack itemstack = entityplayer.an.e();
+
+        if (itemstack != null && itemstack.c == Item.au.ba) {
+            entityplayer.an.a(entityplayer.an.c, new ItemStack(Item.aE));
+            return true;
+        } else {
+            return false;
+        }
+    }
+}