Client doesn't pass back HTTP response status codes with errors

[eatyourgreens]

This piece of code triggers a 422: unprocessable entity from Panoptes by posting a malformed classification.

classification.metadata = {}
classification.save().catch( function(e){ console.log(e); } );

e comes back as Error: {"metadata"=>"did not contain a required property of 'workflow_version'"} so it's impossible to tell this failed with a 422. Consequently, it's not possible to write client code that decides on an error handling strategy based on the HTTP response eg. queue failed classifications in case of a 500 or 503, but not in case of a 404 or 422.

[eatyourgreens]

Closed by #63