fix help for sx-addr command, so it includes fact that this will work for public as well as private key
fix help for sx-addr command, so it includes fact that this will work for public as well as private key

cancoin/libbitcoin-explorer,kaostao/sx,BWallet/sx,kaostao/sx,GroestlCoin/libgroestlcoin-explorer,BWallet/sx,tuomassiren/libbitcoin-explorer,libmetrocoin/libmetrocoin-explorer,libtetcoin/libtetcoin-explorer,GroestlCoin/libgroestlcoin-explorer,kaostao/sx,libtetcoin/libtetcoin-explorer,GroestlCoin/libgroestlcoin-explorer,BWallet/sx,tuomassiren/libbitcoin-explorer,libmetrocoin/libmetrocoin-explorer,cancoin/libbitcoin-explorer