Added proper support for Custom EntityTypes. Fixes #16, #361

All custom mod living entities will now use the CraftCustomLiving class
in order to relay information to plugins. This class is dynamic and will
return the proper type through getType() for the specific entity that sent
the event. All names will be stored as ModName.EntityName to avoid conflicts
with other mods. For example : If you get hit by an Ogre from MoCreatures,
the Damage event type will now display it as MoCreatures.Ogre. Hope
this helps plugins =).