Added EnderChest multi-inventory support

So this should, as with all my code untested, support ender chests within my inventory handler.

I've continued on my pretty big inventory handler to add an extra stage of handling ender chests. This will be put in the database, loaded and saved as with all the rest of the inventory.

No reason for it not to work, my current system hasn't failed yet?

Mainly for the new world - As we need independent ender chest for that