All services now checks whether there inputs and outputs are actually readable by the requesting user,

..to avoid empty objects with no data. All unit tests now succeed again.
#5: RestServices now uses application/json instead of text/json

Which is the official contenttype. Fixes #5. For maximized and backward compatibility (when publishing), anything 'json' is accepted.
If no contenttype is set, and no binary data is expected, fall back to JSON.
Couple of renames to made the code easier to understand

ServiceDefinition -> DataServiceDefinition
PublishedMicroflow -> MicroflowService
PublishedService -> DataService
Fixed #8: any output (even none) is now acceptable for published microflowservices.
the type of primitive type null in jsonschema is "null", not null, which would represent no type. savvy?
null is now accepted for string values when parsing. Fixes #9