Replaced iter_connected_role by iterclients

        for login in to_unregister:

            self.db.unregister(login)

    def iter_connected_role(self, role=None):

        '''

        Generator to iter on each connected client with specified role. If role

        is None, return all connected clients.

    def iterclients(self, role=None):

        """ Iterate over connected clients with an optionnal role filter.

        :param role: role to filter

        '''

        """

        for login, client in self._clients.items():

            if role is None or client.role == role:

        for client in self._clients.itervalues():

            if role is None or client.ROLE == role:

                yield client

    def authenticate(self, conn, login, password):