Fix Craft Entity constructors and toStrings.

Also, standardise getHandle and clean up in general.
getHandle is now using the 'entity' member variable instead of
super.getHandle, as this reduces the number of chained calls needed.

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

@@ -7,16 +7,21 @@ import org.bukkit.entity.ComplexEntityPart;
 import org.bukkit.entity.ComplexLivingEntity;
 
 public class CraftComplexPart extends CraftEntity implements ComplexEntityPart {
-    public CraftComplexPart(CraftServer server, Entity entity) {
+    public CraftComplexPart(CraftServer server, EntityComplexPart entity) {
         super(server, entity);
     }
 
     public ComplexLivingEntity getParent() {
-        return (ComplexLivingEntity)getHandle().a.getBukkitEntity();
+        return (ComplexLivingEntity) getHandle().a.getBukkitEntity();
     }
 
     @Override
     public EntityComplexPart getHandle() {
-        return (EntityComplexPart)super.getHandle();
+        return (EntityComplexPart) entity;
+    }
+
+    @Override
+    public String toString() {
+        return "CraftComplexPart";
     }
 }