add encode_hash() for bare hashes now that stream operator is gone.
add encode_hash() for bare hashes now that stream operator is gone.

libmetrocoin/libmetrocoin-node,libjetcoin/libjetcoin-node,libtetcoin/libtetcoin-node,libjetcoin/libjetcoin-node,libjetcoin/libjetcoin-node,libtetcoin/libtetcoin-node,libmetrocoin/libmetrocoin-node,libtetcoin/libtetcoin-node,libmetrocoin/libmetrocoin-node