DOCS: add Keccak11 and Security03 bibliography references
DOCS: add references.bib to tarballs
RCORE: add KeccakPRNG, a CSPRNG
BUILD: using OPTIMIZE_FAST for randomhash.cc boosts keccak by factor 7.5
RCORE: document KeccakPRNG::result_type
RCORE: add generate<>() method to allow KeccakPRNG use as seed sequence
RCORE: add SHA3_512 and sha3_512_hash()
RCORE: add SHAKE256 and shake256_hash()
RCORE: add SHAKE128 and shake128_hash()
RCORE: add SHA3_224, SHA3_256 and SHA3_384 plus sha3_*_hash() variants
RCORE: improve SHA3 documentation, reference Fips202
RCORE: add class Entropy to gather and distribute randomness
RCORE: add simplistic startup entropy tests
RCORE: add random int, float and range generating functions
RCORE: add documentation for class Entropy
RCORE: seed Entropy also from MAC addresses and VM stats
RCORE: seed Entropy from multiple process statistics
RCORE: add bootup file timestamps to Entropy
RCORE: get Entropy MACs through sockets instead of expensive /sys/ globbing
RCORE: implement RandomNumberEngine.disard() for KeccakPRNG