[conformal/btcutil] 1caa15: Add a testable example.

[Dave Collins]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcutil
  Commit: 1caa150b5c4007c93be597c473abb7a05f1bd399
      
https://github.com/conformal/btcutil/commit/1caa150b5c4007c93be597c473abb7a05f1bd399
  Author: Dave Collins <da...@conformal.com>
  Date:   2014-07-09 (Wed, 09 Jul 2014)

  Changed paths:
    A bloom/example_test.go

  Log Message:
  -----------
  Add a testable example.

This commit creates and an example test file that integrates nicely with
Go's example tooling.

This allows the example output to be tested as a part of running the
normal Go tests to help ensure it doesn't get out of date with the code.