First pass at a test suite

There are two ways of running the tests:

1. Run on your local code (`make test`). The will be "compiled" and run
   inside an HTTP server. Selenium will talk to that server.

2. Against a remote location
   (`APP_URL='pilotplanner-staging.sealevelresearch.com' make test`)

This uses Python, unittest and Selenium to run a bsic test suite against
the site you choose.

[#75571918]
Merge pull request #25 from sealevelresearch/selenium-tests

First pass at a test suite