Version control of notebooks

[bonh]

To fix #3 we have to decide how we want to include notebooks in the project.

There are two dominant tools: https://nbdime.readthedocs.io/en/latest/ and https://jupytext.readthedocs.io/en/latest/.

As far as I understand nbdime wraps around git to allow the usual commands to work directly with notebook files. In contrast, jupytext synchronizes python scripts and notebook files, git is used only on the python scripts, and notebooks are created on the fly.

Both packages are active and widely used. jupytext seems to have more widespread usage but nbdime is developed as part of jupyter.

If version control is directly conducted on the notebooks (nbdime) the notebooks can be rendered in github. But if the version control is performed on the python scripts (jupytext) the examples can be executed headless and copy and past is easier.

Whatever we end up using both can be easily replaced, I think.

[bonh]

nbsphinx makes use of jupytext: https://nbsphinx.readthedocs.io/en/0.8.9/custom-formats.html