Change swagger generator to reference schemas

[stuartpullinger]

The swagger generator includes the structure of the response inline: for example, here the structure of a /datafiles response in included inline. The swagger code generator takes these responses and autogenerates models for them with names like inline_response_200_7. We need to move them to the named schema sections at the end of the file and use references to point to them - as described here. This will enable the code generator to create properly named models for them and have the added benefit of reducing the spec file size a little!