Add partial_fit in Potato

[qbarthelemy]

This PR:

• add function partial_fit() in Potato, useful for online update;
• complete tests;
• update example on artifact detection.

[qbarthelemy]

@lkorczowski has put the artifact detection example in a Python notebook here:
https://github.com/lkorczowski/BCI-2021-Riemannian-Geometry-workshop/blob/master/notebooks/plot_detect_riemannian_potato_EEG.ipynb
with a nice javascript animation, adding these lines at the end

from IPython.display import HTML
plt.rcParams["animation.html"] = "jshtml"
potato

Following this idea, I try to add these lines:

from IPython.display import HTML
plt.rcParams["animation.embed_limit"] = 10
HTML(potato.to_jshtml(fps=5, default_mode='loop'))

But, in the new documentation, the last figure is plotted two times: with plt.show() and then with HTML(potato.to_jshtml()).
I don't know how to detect when code is executed in a ipynb, and in this case, do not call plt.show(). Any idea?

[agramfort]

besides LGTM

[agramfort]

merge if happy @qbarthelemy

[sylvchev]

All good to me!

[sylvchev]

I don't know how to detect when code is executed in a ipynb, and in this case, do not call plt.show(). Any idea?

This could be useful: https://stackoverflow.com/a/22424821

[agramfort]

@lkorczowski green button is yours