Improved readability by adding a few private named methods in Delivery. 

Using == for enum comparisons.

Removed unused DomanObjectUtils class.

Made all immutable fields final, setting to null in package local no-args ctor (Hibernate will stil be able to set fields in runtime).

Added javadoc on Cargo.

Removed "empty itinerary" null pattern object, since a cargo is not always supposed to have an itinerary. More work left here though.

Moved EventSequenceNumber to handling aggregate.

HandlingEvents now have a unique sequence number, and CargoUpdater looks events based on that to update the cargo in question.

First version of pessimistic locking of cargo during rerouting.

Cargo is now a facade for aggregate-internal classes Delivery and Projections.

Delivery calculates current voyage, last known location and transport status on the fly.

Introduced a tracking id generator domain service for getting next tracking id, instead of doing it in the cargo repository.

Migrated parts of the code base to use the cargo.handled(HandlingActivity) way of pushing aggregate updates.

Migrating to a much cleaner way to propagate handling updates to the cargo aggregate: Cargo.handled(HandlingActivity).

Moved some logic into *Status enums, making them richer.

Improvements to a number of toString()s