Create new events to inform listeners of rehashing and consistent hash changes

In relation to http://community.jboss.org/message/529547#529547
It's an well known scenario to start a cluster, and only after the ENTIRE cluster is started to start and do work. Right now, we have CacheStarted and ViewChanged notifications. First only tells us that the local node is started but other nodes might still be in the process of starting. Second one tells us that the view has changed, but not that the cluster has started, i.e. the cache might be in the process of rebalancing state etc.
A possible solution would be to have an NodeJoined event, that would be called whenever a new node finished joining the cluster. Finished joining means state transfer happened and that node is started.
For a possible workaround to this feature see the forum post.