Hash: add sha256-96 and sha512-96

IPSec uses them and some versions of OpenSSH use them (even though RFC6668 makes no mention of them)
Hash: add unit tests
Hash: fix unit tests
Hash: one more fix to unit test
Hash: apply fixes to sha512 unit tests as well
Merge pull request #446 from terrafrost/hash-96-2

Hash: add sha256-96 and sha512-96

* terrafrost/hash-96-2:
  Hash: apply fixes to sha512 unit tests as well
  Hash: one more fix to unit test
  Hash: fix unit tests
  Hash: add unit tests
  Hash: add sha256-96 and sha512-96