Added PyPy support
This will require a bit more work.
On PyPy we can use psycopg2-cffi.
Let me clone that branch. The build will pass soon.
 I think pip is being silly here. Lemme check.
 Now it skips the damm Cython generation step. I'll get back to you on that.
 Closing for now, if you plan to re-open would you mind rebasing the existing commits into a single commit?
 I wouldn't. It doesn't work yet though.
 I mean I wouldn't mind rebasing...
 Cool, I guess I should ask: is this something you plan on continuing to hack on until it's all working? If so be happy to reopen and you can rebase when it's closer to being done.
