Update District retrieve to take auth key as an argument

We have a bunch of districts which we interact with and we need to be
able to use the API for different districts and we cannot rely on
setting it globally once.
Have VCR match requests that might have a `?` at the end

I'm running this under Ruby 2.0, I think there were some changes in URI
that are causing the request URIs to have or not have a trailing
question mark (when there are no params) that causes the requests in the
cassettes to not match up. Support both these forms.
Updates failing tests to allow playback repeats.

These tests were failing because they could not find the /students or /sections urls; but the reason was because the test already used those urls.
Fixes rubocop violations.

Most were autocorrected. Disabled the ClassLength check on CleverObject for now, because it is not too bad (108/100) and also because we don't want to refactor it at this time.
Satisfies the YARD threshold of 100% documentation.
Merge pull request #47 from thinkthroughmath/cln/update-from-upstream

Update districts to optionally use an auth token for retrieval