Pip installation

[SengerM]

This is part of PR #239 in the openEMS project repository.

[thliebig]

How does this solve where to find the necessary binaries? Especially on Windows? Usually the user would expect that after "pip install CSXCAD" everything needed gets installed?
I guess this still needs to have CSXCAD/openEMS installed in some way beforehand? I guess we just have to accept that?

[SengerM]

It does not solve that, unfortunately. TBH, I don't know how to make it better, other than shipping everything together with predefined paths in some installation script, or so.

[thliebig]

@SengerM can you have a look at the conflict?

[thliebig]

I do not like the enforcement of the environment variable... This is not how I prefer to build the python extension (during development) and I think this would break the current build process used by openEMS and potentially other tools depending on CSXCAD...