doc Wiki re-org note on Jupyter on GitHub from Ben

[Bob Carpenter]

The Jupyter notebooks will render on GitHub

https://github.com/blog/1995-github-jupyter-notebooks-3

But that doesn't make them interactive, right? It's just
a static snapshot?

I believe there's also a way to get knitr to render there,
too:

https://github.com/yihui/knitr-jekyll

- Bob