* Added ChildReaper. This builds on the newly added Reaper. This utility monitors a single node
and reaps empty children of that node.
* Issue 107: The namespace wrapper was corrupting the path if the EnsurePath handler had an error.
The best thing to do is let the code continue.
* Issue 109: Make duplicate close() calls in CuratorFrameworkImpl a NOP instead of an error.
* A more complete solution for background build-ups. The previous implementation did the retry sleep
in the background process which ends up blocking ZooKeeper. During connection problems, this would
cause ZooKeeper packets/watchers to back up. The new implementation uses a DelayQueue to simulate a
sleep in the background. NOTE: this caused a change to the RetryPolicy APIs.