A more elegant approach on AuthService.

Cookie handling, REST communcation is performed entirely on AuthService.
Updated .gitignore to ignore vim temporary files
Support for role-based authentication.

First steps for role-based authentication. Each user is given a role
(namely user, programmer and admin) that can access specific resources
(e.g. pages, links). This is illustrated on the navbar, where different
links are shown depending the role a user is assigned.

TODO:
 - Enforce restrictions from routeProvider.