A user authentication module based on flask-security is added, which
allows users to login and change/recover passwords etc. Custom templates
are included for the user/password UIs.
A new setup script will initialise the user (and later settings) DB,
adding the first user and granting them an Administrator role.
A redirects blueprint module is added to handle simple URL redirects.
A browser module is added and currently renders a skeleton page with
a menu bar, gravatar and jumbotron.
NOTE FOR LATER: Currently this code might make the nice basis for any
web app that needs user management and plugins. Hmmm....
