Using Nock to mock network requests

Our tests went from taking ~1 second to run and making legitimate network requests to the API to taking ~80 milliseconds and making no calls to the API or external network. This will greatly stabilize our testing environment and do away with the MockTransporter which is hacky and really just tests our ability to write tests that pass.

I've included Nock here and have updated the tests in question to hit Nock instead. I will rip out the MockTransporter once we merge this.

Bonus: Added tests for query params.