Test nc files

A bit of a strange request. I'm looking at `gcode.parse(...)` the CPython extension function implemented by `gcodemodule.cc`. It is a blocking call from the Python caller's perspective: it initializes an interpreter, opens the file, executes init codes, then loops over `pinterp->read()` and `pinterp->execute()` until the file finishes, an interpreter error occurs, or a Python callback aborts.

I am trying to benchmark a few things and I was wondering if anyone knows of a repository of g-code files for testing?. Basically I'm looking for a small set of .ngc files: small known-good, medium CAM, large CAM, arc-heavy, and many-short-segment. I could create some, but I thought I'd ask if a set already existed.