------------------
Initial release.
This version is functionally equivalent to scrapylib's v1.7.0
``scrapylib.deltafetch.DeltaFetch``.
The only (and major) difference is that support for ``bsddb`` is dropped
in favor of ``bsddb3``, which is a new required dependency.
.. note::
`bsddb`_ has been deprecated since Python 2.6,
and even removed in Python 3
.. _bsddb: https://docs.python.org/2/library/bsddb.html