minor issue - Depends on pycodeexport (but not listed anywhere)

[dlivitz]

I went through all the steps to install this with pip, but couldn't get it to work
tests worked fine for pycvodes, but failed for pyodesys (just the native part)

eventually tracked it down to pycodeexport not being installed, and that fixed the issue.

[bjodah]

Hi @dlivitz, thank you for reporting this.

It's listed as an "optional depenceny" here:
https://github.com/bjodah/pyodesys/blob/master/setup.py#L81

We could make it a standard dependency because it's just a pure python project. It's needed when using any of the SUNDIALS (pycvodes) or GSL (pygslodeiv2) or Boost (pyodeint) backends, the problem is that I cannot be sure that the user has all of those prerequisites, so I made it an opt in to do e.g.

pip install pyodesys[all]

When I glance over the README I realize that it's not at all apparent, and it should probably be clarified...

[dlivitz]

Thank you, that makes sense!