message: Use regex to test for content type of JSON file
  (sometimes returned with encoding breaking the test unnecessarily)
diff: @@ -275,7 +275,7 @@ describe('Hidden URL', () => {
  it('GET Klingon translation file for "Extra Language" challenge', done => {
  frisby.get(URL + '/i18n/tlh.json')
  .expect('status', 200)
  - .expect('header', 'content-type', 'application/json')
  + .expect('header', 'content-type', /application\/json/)
  .done(done)
  })
  