* using real EventSourcedBehaviorImpl
* using new inmem journal (PersistenceTestKit)
* advantages compared to a "fake" driver
* no difference in implementation details from real thing
* no limitations
* less maintance
* added internal messsages to EventSourcedBehaviorImpl to be able to grab state
and persistenceId
* GetState as InternalProtocol instead of Signal so that it is stashed
* serialization checks, using SerializationTestKit
* better testKitGuardian naming to allow multiple PersistenceTestKit
* support testing of restart
* support failure testing by using PersistenceTestKit
* update doc sample
* apidoc, reference docs, and javadsl
