Make sure a status of 0 isn't treated as correct.
Merge pull request #25 from timothyarmstrong/handle_zero_status_right

Make sure a status of 0 is treated as an error
Handling the case when the JSON response is null during an error when using the js client request method.
Merge pull request #26 from timothyarmstrong/null_json_response

Handling the case when the JSON response is null during an error
Merge branch 'master' of https://github.com/dart-gde/discovery_api_dart_client_generator into m4_breaking_changes