The Universal Minecraft Editor is now the

UNIVERSAL MINECRAFT TOOL

Universal Minecraft Tool

Edit all the data stored in your world quickly and easily with the most intuitive NBT editor available.

It has been remade from the ground up to support virtually every version of Minecraft. Dozens of new features were implemented that make the Universal Minecraft Tool significantly more powerful than it's predecessor. The Universal Minecraft Tool (UMT) is a suite of apps combined into a single program. This means it will do much more than NBT editing. At launch, it also comes with a world converter so you can convert your worlds to another edition/version!
Universal Minecraft Tool Website (New NBT Editor)