[change] WIP: drop pyopenssl in favour of cryptography #131

[nemesifier]

Aims to close #131
Close #162
Close #163
Close #174

[davidjmemmett]

I made a start this morning on fixing some of the tests: https://github.com/davidjmemmett/django-x509/commits/PR178-fix-tests/ - this is far from complete, but I'll keep working on this in my spare time until as many of the tests are fixed (or rewritten) as I can get through.

I don't suppose the latest changes from the master branch would merge into this branch easily? It'd make it easier to merge later on

[davidjmemmett]

I'm struggling with django_x509.tests.test_cert.TestCert.test_extensions; I even went as far as re-implementing the part where it adds UnrecognizedExtension, but I couldn't get it working.

What version of cryptography has ExtensionOID._map?

[davidjmemmett]

I've opened a Pull Request to add some tests for these changes - there are a few which are still broken, but it'll require someone with much more experience with both cryptography and django-x509 than myself.

I hope this helps.
Cheers,
David