Small foldable guitar stand (parametric)

I adapted the great design by capone:
- better parametrisation for thicker rod.
- remove zero-thickness planes.
- added comments (in english).
- removed holes in sides (commented-out).
- made it easier to print parts.

The one in the photo uses an 8mm rod, but I have some 15mm tubes from an old fishing-chair that I intend to use for other stands that are even more lightweight.

When printing I found it better to print the head separately because you can get some junk on the side that has to be cut away due to non-optimal retraction settings when printing everything in one go.