Patch commit b134beb3b7809de6370a93cc5f6a684d6942e2e8 from btcd Author: David Hill <dhill@mindcry.org> Date:   Wed Nov 16 10:43:17 2016 -0500
Patch commit b134beb3b7809de6370a93cc5f6a684d6942e2e8 from btcd
Author: David Hill <dhill@mindcry.org>
Date:   Wed Nov 16 10:43:17 2016 -0500

    txscript: reduce allocs in calcSignatureHash

BitGo/prova,BitGo/prova