Merge branch 'dev'
Added additional ECDSA tests: now includes Ed25519 with SHA256/512, Blake2B 256/512, and Keccak (SHA-3) 256/512.
Renamed IDigest to IHash to better reflect the more common/popular use term.
Added optional NaCl library compatibility to Curve25519 and Ed25519 (they both have a HSalsa hashing step in NaCl).