add watifUntiConnected in handleNewSession to avoid session 0
add test case for handleNewSession(). add log for NPE caused by race condition in ZKHelixManager.disconnect(): zkconnection is close (null) but zkEventThread is still running
1. Message current state update now always use session id inside the
message

2. HelixTaskExecutor will cancel all existing tasks if there is a
session time out

test case to be added
Merge branch 'master' of github.com:linkedin/helix
bump up the version to 0.5.9
bump up version to 0.5.10
bump up version to 0.5.11
When the zkproperty server is not up, do not update znrecords. For
statusupdate only
Merge branch 'master' of github.com:linkedin/helix
add log info for each zk operation
modify a test analyze script
Adding the "Action" option in the alert framework. An alert can now
disable storage node / disable partition if certain alert condition is
hit.
fix one testcase
Add logic in GroupCommit.java such that when first time to write to a
zkPath, see if there is an existing value on that path on zk. If yes,
use the zkValue as the initial value.

A testcase for dropping resource when node dead and up again is added.
Sort the instance names when calculating idealstate
bump up to 0.5.12
update ivy files
refactor ZkBaseDataAccessor to deal with retry. add write through cache to ZkCachedDataAccessor.
Helix-66: add a test case for audo ideal state using leader standby model and empty map field. add zkclient.close() to zkPropertyStore.stop(). add a timeout to zkclient.waitForConnected() in zkHelixManager
use the same seed for each idealstate calculation using shuffling