WIP: Using a notebook + nbconvert to execute code blocks

[maartenbreddels]

This is the initial attempt to use a notebook + nbconvert to produce rich output, as explained in #421. It does not yet do any attempt to make a snapshot of the html or widget output.
I understand the issues with the dependency in nbconvert/nbformat, but this is more of an exploration of what is possible. Note that the dependency could be totally optional.

It renders (most) of the gallery already, except for mayavi:

I added an pandas dataframe example (rendering html) and ipyvolume (rendering a live widget). It would be interesting to connect the widget to a live mybinder kernel!.

Pandas dataframe / html

ipyvolume / ipywidgets

To use notebook+nbconvert you need to set the configuration option:
'executor': 'notebook', and optionally set the jupyter_kernel to something else then the default value of 'python3'.

For other languages, such as C++, we need some language specific template that are injected into the notebook for the timing and memory usage.

[choldgraf]

hey @maartenbreddels - looks interesting! Do you think you could give an idea for the main "pros" of doing things this way? E.g., since Sphinx-Gallery already has its own "run the notebook and collect results" script, what would the main benefit be here? Simplification of the build process by offloading onto a dependency?