Minecraft has a new patch, moving the game to 1.7.2. Changes include:
Crashed worlds now work again.
Disappearing piston fixes.
Piston machine that duplicates blocks is now fixed.
Pistons that caused crashing for multiplayer servers fixed.
When the player opens the inventory while sleeping, the player appears sideways. (When the prior bug was pointing from the camera)
We will post more information as it becomes available.