Fix crash on client disconnect from zookeeper
service/testing/multiple_service_test.cc
remove stray comment
Started ZooKeeper testing utilities
ZooKeeper session can now explicity be expired.
Merge branch 'master' into zk-testing

Conflicts:
	service/testing/multiple_service_test.cc
	service/zookeeper.cc
	service/zookeeper.h
	service/zookeeper_configuration_service.cc
Added a counter to test when watches are triggered
Put ServiceDiscoveryScenario and EchoService classes in separated header files
Rewrote multiple_service_test with ServiceDiscoveryScenario class
Using a different strategy to track watches. Using a map rather than a simple counter
Added some sleeps to avoid random exceptions
Do not attempt to call an invalid std::function if connectHandler is null
Merge branch 'master' into zk-testing
Commented out debugging stuff
Merge pull request #37 from datacratic/zk-testing

ZooKeeper Test Suite