rename project to "soapfish"

The code is sufficiently different from the "soapbox" code maintained by
Flight Data Services to warrant a new name. Unfortunately the soapbox
maintainers made it very clear that they don't have any intention to
relicense their code back to the original BSD (which this fork uses) or
to support dual-licensing so I guess the die is cast.

Having a separate name enables us to distribute the code via pypi without
causing confusion among potential users.
rename SoapfishRequest/Response to SOAPRequest/Response

This matches other naming conventions used in the library (SOAPError).