As the main workhorse of the package, the ClusterControllerBean
provides a unified view of any number of Heritrix instances and all related
objects within a JNDI scope.
As the workhorse of the cluster controller client, this class is responsible
for connecting to the local or remote ClusterControllerBean via
its DynamicMBean interface.
Synchronizes the container list with the fresh list (fresh meaning, last
polled from jndi), removing those that went away, and adding any newly
discovered containers.