- add support for multi-node zk cluster
fix multi-servers support for zk

- add myId creation
fix zoo.cfg (was zookeeper.properties) to use correct myid values (makes no difference when ports are the same, but...) and a separate leader port (which is required)
Merge pull request #1126 from ahgittin/zookeeper

ZooKeeper ensembles, some fixes building on #1114