Ch ch ch changes

After experiencing some funny behavior with http://validator.openbadges.org, I thought I'd spend a day working with the code and trying out some new ideas. The changes include:

* a restructuring based on several patterns used in `aestimia`
* bunyan logging as seen in `openbadger`
* some progessive enhancement-y stuff (although the validator service was already doing some, which is cool), including server-side rendering with `nunjucks`
* tests using `mocha`, `supertest`, and `cheerio`