All items/blocks in chests disappear.

Put the summary of the bug you're having here

What I expected to happen was...:
Er, Nothing.

What actually happened was...:
Switching from snapshot to official version causes items in chests to disappear.

Steps to Reproduce:
1. Turn on snapshots.
2. Create a world, place down a chest, and put an item/block in.
3.Quit Minecraft.
4. Go back into Minecraft with the snapshots off.
5. Go into your world and check your chest, Nothing is in there.