nettle-0.2.0: safe nettle binding

# nettle-0.2.0: safe nettle binding

safe binding for the nettle (http://www.lysator.liu.se/~nisse/nettle/nettle.html) library. Tested with 3.1.1, might work with 3.0, does NOT WORK with 2.x.

Modules

- Crypto
  - Nettle
    - Crypto.Nettle.CCM
    - Crypto.Nettle.ChaChaPoly1305
    - Crypto.Nettle.Ciphers
    - Crypto.Nettle.HMAC
    - Crypto.Nettle.Hash
    - Crypto.Nettle.KeyedHash
    - Crypto.Nettle.UMAC