================
- Add the ``mark_error_retryable`` function in order to easily mark
certain errors as retryable for ``pyramid_retry`` to detect.
See https://github.com/Pylons/pyramid_retry/pull/8
- Add the ``IBeforeRetry`` event that can be subscribed to be notified
when a retry is about to occur in order to perform cleanup on the
``environ``. See https://github.com/Pylons/pyramid_retry/pull/9