This event manager keeps track of the changes that take place during a transaction or replication, and batches the changes so
that clients can choose to process the changes as a whole, instead of individual events.
Implementations of this listener may be registered with instances of org.openanzo.common.ontology.ACL to
receive notification when properties changed, added or removed.
Subject grounding that ensures the acl is not deleted for the last transaction timestamp that the query is using and
acl is the default acl template for a user.