Set up some sort of CI

[mjtamlyn]

No description provided.

[jpic]

I can sure make a .travis-ci.yml blindfolded, but I think circleci is vastly superior.

Perhaps we should try both and see what works best ?

We'll also need codecov integration for unit tests, both for python and js (unless you intended to ship HTML forms without JS like in the 90s).

It should also run QA checks (flake8 ?), and a "strict" docs build (fail if sphinx raises a warning).

Feel free to assign this issue to me if you want me to make such a setup for you (perhaps consider validating or closing #25 first !)

[mjtamlyn]

I have used both, at the time Travis was the standard for open source projects, but I don't really mind either way.