Change metadata string to Array (to conform to new requirements)
  Update related test.
Add support for the :format option
Update http method from GET to POST
  Add :format option
  Update :size into :sizes option (in request)
  Update related http test/spec
Add checksum and multimedia to metadata formats
Update README to reflect new format option
  Add checksum and multimedia metadata formats
  Fix typo in one of the basic examples
Merge pull request #6 from jonahoffline/change_request_params_and_http_method

Change request params and http method