Better Rotten Flesh

Adds a new flesh item. It's like rotten flesh except... not rotten. There are two ways to obtain it:

1. Crafting any meat surrounded by 8 rotten flesh
2. Enchanting a sword with Preservation and killing a mob that would normally drop rotten flesh (like a zombie)

It can be eaten without any hunger effect as an alternative food when out at night as well as be smelted in a furnace into leather.

A bone surrounded by 8 rotten flesh can now be crafted into a decorative zombie head.