Inventory and chest problems.

Put the summary of the bug you're having here

What I expected to happen was...:
I thought i could use my 1.7 world in the 14w07a snap shot.

What actually happened was...:
I enter the world in the 14w07a snap shot and boom. all the items of my chests, inventory, and furnaces were gone.

Steps to Reproduce:
1. create a world in 1.7 and put items/blocks in your inventory
2. enter the world in a 1.8 snap shot
3. notice all the hard earned items in your inventory are GONE