Cleanup settings

* Create settings_common for shared settings.
* Create settings_production for production settings (minus sensitive
  information). Sensitive information should be stored on the server,
  not in git.
* Updated mysql-python to use 1.2.5 (it wouldn't install on 1.2.4 for
  me).
* Update references to settings to point to app.config
Add empty public dir for Passenger
Add passenger_wsgi loader
Add tmp/ to gitignore