If a LazyEntityReference receives a version parameter, use that instead of trying to retrieve the current version from the DB
When serializing a LazyEntityReference to JSON, use plain "id" instead of "entity_id"
Fix for object_tracker not resolving LazyEntityReferences correctly
Merge pull request #38 from mcamou/master

LazyEntityReference fixes: use the given version if passed in, JSON serialization and object_tracker