Configurable public address.

- Make {site_root}/bin/{site_name} a script instead of a symlink
- Configure the public and listen addresses in {site_root}/etc/default.ini
- Add hacking 0.8.0 as a requirement, to get the H306 warning from flake8
flake8/hacking fixes.
Update tests to account for the new public attribute in ServerConfig.
Move hydra code around.