Add footnote about gh-publisher?

[jakevdp]

Hi – I love this project. I'm using it for my current paper, which you can see here: http://jakevdp.github.io/multiband_LS/

One feature suggestion: it would be nice if the generated webpage had some kind of footer linking to the gh-publisher repo, with a sentence or two about what it is and how it works.

Thanks for working on this!