Relax response's media type

[m0x72]

Currently mocks are only generated for responses of the media type application/json (https://github.com/RePoChO/raml-mocker/blob/master/src/index.js#L156).

Any (custom) JSON media type should be allowed though. As a solution, one may either:

• Mock the first media type matching /application\/[A-Za-z.-0-1]*\+?json/ in the media type map of the response's body property
• Mock all media types matching /application\/[A-Za-z.-0-1]*\+?json/ in the media type map of the response's body property
  • Would require mock() and example() to return either
  • a map of media types
  • default to i.e. application/json or the first media type in the list and providing mockByMediaType() / exampleByMediaType() methods; analogous to mockByCode()

Any inputs? Would be happy to draft a PR :)

[fabiotisci]

@repocho Could you please take a look and merge if you think is right? We are using the server and it's creating problems with custom media types. Cheers

[repocho]

Fixed by #19