Enable use of CRL (and more) in verify context. (#483)

* Enable use of CRL (and more) in verify context.

* flake8 fixes.

* Comments from Hynek & Paul.

* More updates from Paul & Hynek.

* Fix closing backtick.

* Remove commented out constants.

* More doc updates. Changelog update.

* Getting closer?

* Sphinx fix.

* Indent docstring.

* More Sphinx updates.

* Type updates for docstrings.

* Remove Enum subclassing.

* Docstring update.

* Docstrings updates.

* Round and round it goes. Where it ends, nobody knows.

* Remove TODO comment. Need @sholsapp to follow up.

* Time for lots of alcohol.
4 files changed