Rudder

When an API is deprecated, it must be apparent in the response.

We need:
- an optionnal deprecation attribute in our JSON response, defaulted to false.
- an header. Internet does not seems to have a convention on it: http://stackoverflow.com/questions/12506817/http-header-field-for-uri-deprecation-expiration

For consistancy, both attribute should be the same (modulo case).

I propose to simply use: "deprecated".