Move to Swagger 2.0

See: [Swagger 2.0 Spec](https://github.com/wordnik/swagger-spec/blob/master/versions/2.0.md)
To keep distributable size down. I've started doing it as tests can grow rather large and there's not a lot of value in packaging them with the distributable IMO. Git repos are easy enough to find and if people need to find the readme chances are they've found the repo containing the tests already.