Custom MIME type for error and configuration response #55
Description
Instead of returning a generic Content-Type of application/json, both error response and configuration response should use a custom MIME type, for example text/micropub-error+json and text/micropub-configuration+json.
Clients may validate the returned JSON against a schema when they get a specific content type.
They can also see that the server sends the correct data, and not just some standard error garbage that's not readable by clients expecting a specific data format.
Using custom MIME types is also suggested by http://jsonapi.org/format/#content-negotiation-servers