Trigger concept and Dynamic event binding
Removes Merchello version from the merchello.config
EventTrigger resolution
EventTriggerRegistry and dynamic binding to Merchello service events
Missed files
Patched up unit tests
Bit of clean up in the EventTriggerRegistry - may still need to refactor and separate out the resolver from the registry so that we can inject services (or MerchelloContext) into individual triggers.
Removed NotificationTrigger model, repository, mappers and factories now that these are to be handled by resolved objects and event binding.