* sha3 family of hash functions
* shake variable length hashes that were introduced alongside sha3
* blake2 family of hash functions
* Mark VarLenHash as a private class, since it's not actually exported by hashlib
* Fix typos in my last, and mark hashlib.Hash as a private class since it isn't in the real hashlib
* Update pbkdf2_hmac for Python 3.5
- Use `iterations` instead of `rounds` if running on 3.5
- Change `dklen` to `Optional`
* Use `iterations` instead of `rounds` in 3.4+
