Added AsyncManager.iter iterator.

             >>> for msg in watcher.wait(timeout=60):

             >>>     process(msg)

        '''

        responses = []

        return list(self.iter(timeout, max_wait))

    def iter(self, timeout=None, max_wait=None):

        '''

        Work like :meth:`AsyncWatcher.wait` but return an iterable, instead of

        a list object.

        .. note::

           Responses are yielded by the iterable when they are received, so you

           can start the processing of response before receiving all.

        '''

        while self.remains:

            try:

                dt, response = self._get_in_queue(timeout=timeout)

                break

            if timeout is not None:

                timeout -= dt

            responses.append(response)

            self._expected_responses.remove(response['id'])

            yield response

            # Check for max_wait:

            if max_wait is not None:

                max_wait -= 1

                if not max_wait:

                    break

        return responses