first commit; things working right now
tests
Merge branch 'master' into batch-zk
Merge branch 'master' into batch-zk

Conflicts:
	client/src/main/java/com/metamx/druid/QueryableNode.java
fix according to code review
Merge branch 'master' of github.com:metamx/druid into batch-zk

Conflicts:
	server/src/main/java/com/metamx/druid/coordination/ZkCoordinator.java
	server/src/main/java/com/metamx/druid/loading/SingleSegmentLoader.java
fix concurrency problem
Merge branch 'master' of github.com:metamx/druid into batch-zk
another thread safety fix
announcer thread fixes
Merge pull request #170 from metamx/batch-zk

Enable batched ZK announcements