[conformal/btcutil] fdb279: Use fastsha256 in Hash160.

[Dave Collins]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcutil
  Commit: fdb279f4827d062f665aa5e29e24ee62bf9d712b
      
https://github.com/conformal/btcutil/commit/fdb279f4827d062f665aa5e29e24ee62bf9d712b
  Author: Dave Collins <da...@conformal.com>
  Date:   2014-01-04 (Sat, 04 Jan 2014)

  Changed paths:
    M hash160.go

  Log Message:
  -----------
  Use fastsha256 in Hash160.

Rather than using the stdlib sha256, use the Conformal fastsha256 package
for faster hashing.