[conformal/btcwire] b830e2: Add benchmarks for readVarString.

[Dave Collins]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcwire
  Commit: b830e2ddf3ed719889d1c11da8d73ef09d82a68b
      
https://github.com/conformal/btcwire/commit/b830e2ddf3ed719889d1c11da8d73ef09d82a68b
  Author: Dave Collins <da...@conformal.com>
  Date:   2013-11-05 (Tue, 05 Nov 2013)

  Changed paths:
    M bench_test.go

  Log Message:
  -----------
  Add benchmarks for readVarString.

This commit adds a few benchmarks for the readVarString function.