deploy / undeploy / update on the ControlledDynamicWebAppCluster

This works & tested.  However, need to discuss the following

=> resize etc the cluster.  Currently, the war will not propagate to new cluster members.  We should at least store the URL from where it was fetched and auto-push. 
=> are there any subclasses (Cluster of ...) that need these as well?
=> What if the war file at the URL changes? or vanishes?  what is the predictble behavior?