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/EntityPigZombie.java

@@ -0,0 +1,100 @@
+package net.minecraft.server;
+
+import java.util.List;
+import java.util.Random;
+
+public class EntityPigZombie extends EntityZombie {
+
+    private int a;
+    private int b;
+    private static final ItemStack f;
+
+    public EntityPigZombie(World world) {
+        super(world);
+        a = 0;
+        b = 0;
+        aP = "/mob/pigzombie.png";
+        bC = 0.5F;
+        c = 5;
+        ae = true;
+    }
+
+    public void b_() {
+        bC = d == null ? 0.5F : 0.95F;
+        if (b > 0 && --b == 0) {
+            l.a(((Entity) (this)), "mob.zombiepig.zpigangry", i() * 2.0F, ((W.nextFloat() - W.nextFloat()) * 0.2F + 1.0F) * 1.8F);
+        }
+        super.b_();
+    }
+
+    public boolean b() {
+        return l.k > 0 && l.a(z) && l.a(((Entity) (this)), z).size() == 0 && !l.b(z);
+    }
+
+    public void a(NBTTagCompound nbttagcompound) {
+        super.a(nbttagcompound);
+        nbttagcompound.a("Anger", (short) a);
+    }
+
+    public void b(NBTTagCompound nbttagcompound) {
+        super.b(nbttagcompound);
+        a = ((int) (nbttagcompound.c("Anger")));
+    }
+
+    protected Entity l() {
+        if (a == 0) {
+            return null;
+        } else {
+            return super.l();
+        }
+    }
+
+    public void o() {
+        super.o();
+    }
+
+    public boolean a(Entity entity, int i) {
+        if (entity instanceof EntityPlayer) {
+            List list = l.b(((Entity) (this)), z.b(32D, 32D, 32D));
+
+            for (int j = 0; j < list.size(); j++) {
+                Entity entity1 = (Entity) list.get(j);
+
+                if (entity1 instanceof EntityPigZombie) {
+                    EntityPigZombie entitypigzombie = (EntityPigZombie) entity1;
+
+                    entitypigzombie.g(entity);
+                }
+            }
+
+            g(entity);
+        }
+        return super.a(entity, i);
+    }
+
+    private void g(Entity entity) {
+        d = entity;
+        a = 400 + W.nextInt(400);
+        b = W.nextInt(40);
+    }
+
+    protected String e() {
+        return "mob.zombiepig.zpig";
+    }
+
+    protected String f() {
+        return "mob.zombiepig.zpighurt";
+    }
+
+    protected String g() {
+        return "mob.zombiepig.zpigdeath";
+    }
+
+    protected int h() {
+        return Item.ap.ba;
+    }
+
+    static {
+        f = new ItemStack(Item.E, 1);
+    }
+}