- Add tests to validate that bucket list streaming is working.
- Add tests to validate that timeouts are working correctly for
  all variations of list buckets and list keys (stream and non,
  timeouts too-short and long-enough).
- add intercept in the right place to simulate delays for large
  numbers of keys/buckets returned.
Merge pull request #263 from basho/pevm-stream-timeouts

test for bucket and key listing timeouts