Add events to the list of uncommitted in `Aggregate` only if they are successfully applied to the entity

[dmitrykuzmin]

Currently, the method Aggregate.apply(List<Event> events) always adds all events to the in-memory list of aggregate's uncommittedEvents, ignoring the actual result of applying them to the entity.

When multiple messages are dispatched in a batch, the entities may be cached. In this situation, if the earlier dispatch produces events which render aggregate state invalid, but the following one is successful, all of the events will be actually saved to the storage, forever corrupting the aggregate history.