HDWallet: remove HmacBytesToBytes
HDWallet: adhere to BIP32 for CKD
HDWallet: show clearer BIP32 adherence for Master key
Transaction: remove untested hash array support
convert: remove hex functions
crypto: HMACSHA512 into crypto and add tests
Merge pull request #174 from dcousens/hdbipad

HDWallet BIP32 adherence
Merge pull request #175 from dcousens/cryptoHmac

Consolidation of crypto functions