Add gemset and ruby version.
Gemfile update.

* Set some explicit faraday & co requirements
* Replace rcov with simplecov.
Rakefile updates.

* Properly load the lib
* Update testtask
* Remove rcov task.
MultiJson does not like nil bodies.

Do we need to more explicitly protect against sending them, or is this
just a test issue?
Update to the confusingly named Reponse class.

* There are points at which this response is expected, or an array or
hash is expected. Therefore, response should know how to respond to some
methods like an array or hash.
Configuration.base_uri added, to replace BASE_URI.

* Like the api_endpoint, the base_uri is env-depdendent.
Remove a bad char.
Use Configuration.base_uri instead of BASE_URI.