Add basic HTTP authentication to archive POST/DELETE.

    The credentials can be stored in the charmd configuration file.
    Abstract out the authentication logic in a decorator.
    Created a card for the DoRequest refactoring.
Improve charmd options handling. Renamed the http basic auth realm.
Improve NewServer and auth documentation.
Minor test fixes.
Auth: drop the decorator in favor of a more direct approach.
Decouple the external server params from the internal handler config.
Merge pull request #81 from frankban/basic-auth

Add basic HTTP authentication to archive POST/DELETE.

The credentials can be stored in the charmd configuration file.
Abstract out the authentication logic in a decorator.
Created a card for the DoRequest refactoring.