Fixed CraftLivingEntity.damage when the entity is an EntityComplex.

Fixes BUKKIT-589: if you call damage on an instance of EnderDragon, no damage
is done.

Reason for bug: damage calls Entity.damageEntity.  But EntityComplex
overrides damageEntity to do nothing.

Fix: CraftComplexLiving should call EntityComplex.e instead of
Entity.damageEntity.  e is the method that actually does damage to an
instance of EntityComplex.

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

@@ -0,0 +1,26 @@
+package net.minecraft.server;
+
+public class EntityComplex extends EntityLiving {
+
+    protected int t = 100;
+
+    public EntityComplex(World world) {
+        super(world);
+    }
+
+    public int getMaxHealth() {
+        return this.t;
+    }
+
+    public boolean a(EntityComplexPart entitycomplexpart, DamageSource damagesource, int i) {
+        return this.damageEntity(damagesource, i);
+    }
+
+    public boolean damageEntity(DamageSource damagesource, int i) {
+        return false;
+    }
+
+    public boolean e(DamageSource damagesource, int i) { // CraftBukkit - protected -> public
+        return super.damageEntity(damagesource, i);
+    }
+}

src/main/java/org/bukkit/craftbukkit/entity/CraftComplexLivingEntity.java

@@ -1,9 +1,11 @@
 package org.bukkit.craftbukkit.entity;
 
+import net.minecraft.server.DamageSource;
 import net.minecraft.server.EntityComplex;
-import net.minecraft.server.EntityLiving;
 import org.bukkit.craftbukkit.CraftServer;
 import org.bukkit.entity.ComplexLivingEntity;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.entity.LivingEntity;
 
 public abstract class CraftComplexLivingEntity extends CraftLivingEntity implements ComplexLivingEntity {
     public CraftComplexLivingEntity(CraftServer server, EntityComplex entity) {
@@ -19,4 +21,21 @@ public abstract class CraftComplexLivingEntity extends CraftLivingEntity impleme
     public String toString() {
         return "CraftComplexLivingEntity";
     }
+
+    @Override
+    public void damage(int amount, org.bukkit.entity.Entity source) {
+        DamageSource reason = DamageSource.GENERIC;
+
+        if (source instanceof HumanEntity) {
+            reason = DamageSource.playerAttack(((CraftHumanEntity) source).getHandle());
+        } else if (source instanceof LivingEntity) {
+            reason = DamageSource.mobAttack(((CraftLivingEntity) source).getHandle());
+        }
+
+        if (entity instanceof EntityComplex) {
+            ((EntityComplex) entity).e(reason, amount);
+        } else {
+            entity.damageEntity(reason, amount);
+        }
+    }
 }