Log Message:
py-html5lib: update to 1.1.

Add some missing dependencies and test dependencies.

1.1
~~~

Breaking changes:

* Drop support for Python 3.3. (#358)
* Drop support for Python 3.4. (#421)

Deprecations:

* Deprecate the ``html5lib`` sanitizer (``html5lib.serialize(sanitize=True)`` and
  ``html5lib.filters.sanitizer``). We recommend users migrate to `Bleach
  <https://github.com/mozilla/bleach>`. Please let us know if Bleach \ 
doesn't suffice for your
  use. (#443)

Other changes:

* Try to import from ``collections.abc`` to remove DeprecationWarning and ensure
  ``html5lib`` keeps working in future Python versions. (#403)
* Drop optional ``datrie`` dependency. (#442)