totally renewed hierarchie builder

an eviction channel listenes for successful database inserts/updates and deletes and performs some kind of I/O to them. For instance a concrete implementation could write all successful changes to the in-memory database to a external database to create a persistent version that can be imported during application ramp-up. Eviction channels can be configured to follow certain timing constraints like immediate post transaction eviction or cron like eviction, that is forwarding all the changes every x seconds. Invariants are: (1) Eviction is asynchronous to to the actual transaction, (2) Eviction might fail but to not cause the transaction to fail.

An Eviction Channel that uses a Couch DB server to load persistent data and to backup all transaction to. The couch db server
is supposed to run on http://localhost:5984 or as per JVM System Parameter -Dcouchdb.url or individually configured per eviction channel instance