Removed some noisy logging for persona.
Refactor db code.

- Use generic Go sql interface
- Remove unsafe queries built with string interpolation
- Add tests
Refactor server.

- Use the new API for db backend.
- Expose a new API for app and client site.
- Use a REST framework because I wanted to try one out.
Use the new API on the app.
Use the new API on the site.
Update README with new dependencies.
Run gofmt.
Merge pull request #8 from dougt/server

New backend code and server API