Circle redux

@chriddyp , @scjody , @etpinard 

After trying (and failing) to get TravisCI to run these properly, I just wrote some scripts and stuck them in a `circle` directory --> `setup.sh` and `test.sh` which use environment variables set in the `circle.yml` (which i reinstated).

I cleared all the information from the settings in Circle for the project, I'd much prefer changes to how we test get committed with the repo anyhow...

I *still* can't get the permissions test to work... I'd love to screen share with someone while i ssh into a build so i can show you the source of confusion... i'm sure it's simple, but i'm totally stuck on it.

Other than this, this branch is good to go. It tests 2.6, 2.7, 3.3, and 3.4. Run time is ~7 minutes, which is a little annoying, but honestly now that everything is cached between builds, it's not really any slower than the previous builds. We could run these concurrently in circle... but i'm sure we'll hit intermittent errors since we reach out to plotly's servers in the tests (i say i'm sure because this happened when trying to use Travis).