NuttX (Posix like) RTOS on ODrive v3.3

Yippe-Ya-Yeah, I finally got my ODrive board :-).

I set up a toolchain for NuttX, as this has Posix compatibility and comes with a nice shell.
So far, only communication per USB ACM is working. But more may come.

See https://github.com/skaterkamp/odrive-nuttx.git

Cheers
Stefan