Tests

This sets up tests for most of the base utility functions. Everything else requires the clock being mocked out, so stopping here for now.

With a few more changes, this setup will easily use https://travis-ci.org/ and https://coveralls.io/, both of which are free for open-source repositories. In those cases, we'll get reporting on pull requests as to how they effect test and coverage results.

A few more changes after that (omsmith/valence-sdk-javascript#browserify), we can run the same tests in browsers using https://ci.testling.com/, also for free.

`D2L.Util.getTokenUrl` currently fails 1 case where `path` contains a query string.