Support top-level parameters and responses

[smithje]

I have a number of endpoints that have the same query parameters and responses; not the same schema, but the entire parameter/response is exactly the same. It would be great to use swagger's top-level parameters and responses objects and reference them from the YAML decorating my views, much like we can now do with schema definitions.

Currently, I can define the parameters object on the swag object, but if I try to reference it in my YAML, it just gets converted to null.

[smithje]

I'm sorry, this was my fault. I had not properly quoted the reference. It does seem to work after all.