Add a test showing that the register-transaction event is emitted when  changing an invalidated object that was retrieved in a previous  transaction.
Add a test showing that the register-transaction event is emitted when 
changing an invalidated object that was retrieved in a previous 
transaction.

PyMamba/mamba-storm,petrhosek/storm,PyMamba/mamba-storm,petrhosek/storm,petrhosek/storm,PyMamba/mamba-storm