[conformal/btcwire] cece30: Optimize readTxOut.

[Dave Collins]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcwire
  Commit: cece305f7824208a2ba16d07f7ce8f517e9c015d
      
https://github.com/conformal/btcwire/commit/cece305f7824208a2ba16d07f7ce8f517e9c015d
  Author: Dave Collins <da...@conformal.com>
  Date:   2013-11-06 (Wed, 06 Nov 2013)

  Changed paths:
    M msgtx.go

  Log Message:
  -----------
  Optimize readTxOut.

Before: BenchmarkReadTxOut        500000              4576 ns/op
After:  BenchmarkReadTxOut       2000000               871 ns/op

This is part ef the ongoing effort to optimize serialization as noted in
conformal/btcd#27.