* add ChaCha20Poly1305 test vectors from OpenSSL/RFC7539

* add the boringssl tests as well

* highlight the lines

The OpenSSL manual recommends a buffer size of 80 for OBJ_oid2txt:
https://www.openssl.org/docs/crypto/OBJ_nid2ln.html#return_values.
But OIDs longer than this occur in real life (e.g. Active Directory
makes some very long OIDs).  If the length of the stringified OID
exceeds the buffer size, allocate a new buffer that is big enough to
hold the stringified OID, and re-do the conversion into the new
buffer.

CRYPTOGRAPHY_SUPPRESS_LINK_FLAGS will now suppress link flags regardless
of platform. Additionally, CRYPTOGRAPHY_WINDOWS_LINK_LEGACY_OPENSSL is
now the flag you need if you want to link against < 1.1.0 on windows.

* time to remove commoncrypto, fare thee well

* remove even more

* update the changelog

* remove more things

* don't need this function

* remove CAST5 CTR tests since that was only supported in commoncrypto

* assert a thing

* Refs #3461 -- added a test vector with SCTs

* timestamp is a word