Changes:
Update the badger database using transactions, as supported from yesterday via: 06242925c2
Add a custom `OnActivate` via mvc/activator/activate_listener.go, this can be used to perform any custom actions when the app registers the supported Controllers. See mvc/session_controller.go for the excellent use case.
errors.Reporter.AddErr returns true if the error is added to the stack, otherwise false
Former-commit-id: c896a2d186a4315643f3c5fdb4325f7ee48a9e0a
