. Document md5'd passwords for digest stuff
. Add deprecation notice to old module.
. document & test authorization_required_message
. Test $self->_config->{authorization_required_message} + authorization_required_message = undef does not stamp on body.
. Split auth headers / do auth methods again, and make authenticate call each in turn.
. Document / test 'algorithm' config.
. Test and document use_uri_for config