Test git+nbdime to potentially replace ipyaml to handle Jupyter notebooks

[alixdamman]

@gdementen nbdime provides tools for diffing and merging Jupyter notebooks ( http://nbdime.readthedocs.io/en/stable/index.html ). It is possible to integrate nbdime with git:
http://nbdime.readthedocs.io/en/stable/vcs.html

It could be a good alternative to ipyaml for the tutorial notebooks.

[gdementen]

I didn't know that project. It seems pretty nifty on paper. We should test it to see if it actually works well in practice. We won't be able to use PyCharm git integration, but it is probably a step in the right direction anyway thanks to the ability to diff the output, which is the weak point of the ipyaml solution.

[alixdamman]

For Github integration, we will need to wait a little bit more: jupyter/nbdime#243