Nettle.BlockCipher16: Added new AEAD mode: EAX.
Test vectors from the EAX specification.
FIXME: Nettle only supports EAX with block ciphers having a 16 byte
block size. The actual specification supports any block size. Consider
implementing a generic version as well.
FIXME: Nettle also has an AES-specific implementation of EAX. Consider
adding support for it too.