Yes, that is true. But I'm not working on it any longer. I made a fully working bone-editor, so you can place and link bones to form a skeleton. However, I quit eventually because when I began to develop the actual animation editor, I encountered some heavy problems which I had no idea how to solve.
I think that Phantom107 has been working on something like that. You should PM him to just talk about it. I'm guessing that he canceled the project, or hasn't been able to finish it.
I've uploaded 2 images so you can see how it looked: