add delete operation
add basic support for operations to specify whether the 'Location' response header should be followed or not (if it is present in the response of course)
add optional argument to create/update to specify whether to return the complete new/updated resource or not
update doc comments for create/update with regards to return values
update fhir request response return handling to detect if the body has a json (fhir) response (probably an operation outcome resource) and parse+return it when it makes sense to (in conjunction with the Location header following option)