* Depend on ZooKeeper 3.4.5

* Issue 177: PathChildrenCache wasn't shutting down the executor when closed. Also, reworked the event
queue to avoid potential herding of messages in unstable conditions. The herding could result in runaway
memory allocation as reported in the issue. NOTE: due to this change, the PathChildrenCache node
refresh code and the PathChildrenCacheListener notification threads have been merged. Do not block
for very long inside of your PathChildrenCacheListener or you will prevent the cache from getting
updated.

* Issue 200: Post-creation services registered in ServiceDiscovery via registerService() were
not being treated the same as the service passed in the constructor. Consequently they wouldn't get
re-registered if there were connection problems.

* Creating nodes withProtection() is now supported in the background. e.g.
client.create().withProtection().inBackground()...

* Added methods to InterProcessSemaphoreV2: setNodeData() and getParticipantNodes() and, to the Lease
interface, getData().

* Issue 205 - already started error message was misleading.

* Pull 209 - Fixed inconsistent API for get() in DiscoveryResource.java - thanks to user dougnukem

* Issue 211 - Added getState() method to CuratorFramework.

* Issue 212 - There wasn't a good way to update the data for a Service. I've added a new method
ServiceDiscovery: updateService(). NOTE: this method requires all ServiceDiscovery instances to be using
version 1.2.5 of Curator. Internally, ServiceCache now uses PathChildrenCache.

* Pull 210 - For convenience, a version of {@link DiscoveryContext} that uses any generic type as the
payload. Thanks to user dougnukem.