standardize json error messages via the json_api renderer.
consolidate API request / response spec helpers
do not test status codes to determine errors, pass the error object to  json_api renderer instead

As per Ed's suggestions just pass the error object into the renderer to allow the presenter to format the response correctly.
Merge pull request #62 from camallen/feature-json_error_responses

standardize json error messages via the json_api renderer.
Add cellect configuration to workflow
Conform workflow fields to Cellect
Merge pull request #63 from edpaget/feature-subject_select_config

Feature subject select config
Remove random creation of has_many relations