Update gems, remove deprecated calls in tests, and remove bad tests.

- Update VCR and remove deprecated methods in favor of new ones (see: https://gist.github.com/kincorvia/4540489).
- Configure VCR to hook_into :webmock since :fakeweb has been deprecated.
- RSpec :should was deprecated, change to :expect
- Remove tests expecting RequestDeniedError raised when the :sensor parameter is not supplied as this is no longer the case.

Also, some general cleanup:
- double quotes to single quotes