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/EntityChicken.java

@@ -0,0 +1,78 @@
+package net.minecraft.server;
+
+import java.util.Random;
+
+public class EntityChicken extends EntityAnimals {
+
+    public boolean a;
+    public float b;
+    public float c;
+    public float f;
+    public float ak;
+    public float al;
+    public int am;
+
+    public EntityChicken(World world) {
+        super(world);
+        a = false;
+        b = 0.0F;
+        c = 0.0F;
+        al = 1.0F;
+        aP = "/mob/chicken.png";
+        a(0.3F, 0.4F);
+        aZ = 4;
+        am = W.nextInt(6000) + 6000;
+    }
+
+    public void o() {
+        super.o();
+        ak = b;
+        f = c;
+        c += ((float) ((double) (A ? -1 : 4) * 0.29999999999999999D));
+        if (c < 0.0F) {
+            c = 0.0F;
+        }
+        if (c > 1.0F) {
+            c = 1.0F;
+        }
+        if (!A && al < 1.0F) {
+            al = 1.0F;
+        }
+        al *= 0.90000000000000002D;
+        if (!A && t < 0.0D) {
+            t *= 0.59999999999999998D;
+        }
+        b += al * 2.0F;
+        if (!l.z && --am <= 0) {
+            l.a(((Entity) (this)), "mob.chickenplop", 1.0F, (W.nextFloat() - W.nextFloat()) * 0.2F + 1.0F);
+            a(Item.aN.ba, 1);
+            am = W.nextInt(6000) + 6000;
+        }
+    }
+
+    protected void a(float f1) {}
+
+    public void a(NBTTagCompound nbttagcompound) {
+        super.a(nbttagcompound);
+    }
+
+    public void b(NBTTagCompound nbttagcompound) {
+        super.b(nbttagcompound);
+    }
+
+    protected String e() {
+        return "mob.chicken";
+    }
+
+    protected String f() {
+        return "mob.chickenhurt";
+    }
+
+    protected String g() {
+        return "mob.chickenhurt";
+    }
+
+    protected int h() {
+        return Item.J.ba;
+    }
+}