Remove outputs to enable Github rendering

[Rocketknight1]

This PR uses jupyter nbconvert --clear-output --inplace on our notebook files - some of them were saved with outputs, which went out of date and no longer render properly in GitHub.

Fixes #566

[review-notebook-app]

Check out this pull request on 

See visual diffs & provide feedback on Jupyter Notebooks.

---

Powered by ReviewNB

[Rocketknight1]

cc @NielsRogge since you were in the original issue - are you okay with the change?

[NielsRogge]

Thanks, that's a bit of a bummer, so Github does not allow to see outputs anymore of Jupyter notebooks?

[Rocketknight1]

I think the problem is that the outputs included widget state, but the widget state became old and no longer matched the modern versions of those widgets, so GitHub wasn't able to render it anymore.

A short-term fix is to remove notebook outputs, but we could also have someone rerun all of the notebooks with modern jupyter and re-save them, which should allow them to render on GitHub again