* libre 2.7.3 compatibility

* add a changelog

* actually build against 2.7.3

* Remove defines for openssl 1.1.0 pre

* Update bio.py

* Update dh.py

* Update dsa.py

* Update rsa.py

* Update x509_vfy.py

* Compress branches

RSA_blinding_off is a silly function. RSA_SSLV23_PADDING and
RSA_X931_PADDING are obsolete. The low-level padding functions appear
unused and the EVP_PKEY stuff is probably a bit nicer than expecting
callers to RSA_NO_PADDING and do the padding by hand.

* No more FUNCS/MACROS distinction

* change the docs to not talk about MACROS since they're gone

* remove out of date comment

* Attempt to simplify the libressl checing

* SHENANGINS

* Attempted fix

* More simplification

* delete the 1.0.0 support

* drop the version check

* drop the AES-CTR stuff

* Update the example

* openssl truncates for us now

* delete unused test

* unused imports

* Remove a bunch of conditional bindings for NPN

* no more 1.0.0 builders

* libressl fix

* update the docs

* remove dead branches

* oops

* this is a word, damnit

* spelling

* try removing this

* this test is not needed

* unused import

* Use a series of constants for OpenSSL version checks.

N.B. I removed several qualifiers that were being used to express beta vs. release in OpenSSL version numbers. Reviewers please look closely!

* Convert some python as well, also add the file

* flake8

* Simplify code, remove functionality that can be expressed more simply

* clean up the tests as well

* more constants

* wrap long lines

* reflect feedback

* unused

* add this back?

constify + a few small changes to the null checks