Doesn't work in a lot of programs.

[paulwrath1223]

Programs I've found with compatibility issues when opening file made by this lib:

• Fusion 360 (and other Autodesk apps I've tested)
  • Gives non-specific error and won't open any file made by this lib
• OnShape (insert DXF as sketch)
  • Gives non-specific error and won't open any file made by this lib
• OnShape (open DXF, which uses ARES Kudo for Onshape)
  • Opens, but fails to render arcs in my case.

Obviously the library is working because many other programs work and are able to parse the files, but I was unable to get these programs to work. For now, I've been able to convert the DXF to a DWG online and that works, (although it changes the scale by 10), but because these are such common programs, I believe this library should at least be able to export a compatible file, maybe with a special save_file impl that takes a compatibility enum.

If someone else has gotten these to work with different header parameters, I'd love to know, so far I've only experimented with changing the DXF version. Right now, I plan to make a fork to mess around and see if I can hack in support for those programs and maybe if I identify the problem and am able to make a clean implementation, I'll put a PR in.