Change sighash enum to typedef (for use in sx).
Change sighash enum to typedef (for use in sx).

swansontec/libbitcoin,libtetcoin/libtetcoin-consensus,GroestlCoin/libgroestlcoin,libmetrocoin/libmetrocoin-consensus,libmetrocoin/libmetrocoin-consensus,GroestlCoin/libgroestlcoin,swansontec/libbitcoin,libtetcoin/libtetcoin-consensus,libtetcoin/libtetcoin-consensus,GroestlCoin/libgroestlcoin,GroestlCoin/libgroestlcoin,libmetrocoin/libmetrocoin-consensus,libmetrocoin/libmetrocoin-consensus,swansontec/libbitcoin,swansontec/libbitcoin,libmetrocoin/libmetrocoin-consensus,libtetcoin/libtetcoin-consensus,libtetcoin/libtetcoin-consensus