Event System #13
Description
Requirements: Events should be emitted by the package
This should be done on every update/delete/delete_all handled by the HasPreferences Trait -> 3 Events
An event includes:
- PreferenceGroup (only update/delete)
- PreferencableModel
- Authenticable
- maybe:
- mixed old_value
- mixed new_value(only update, for delete/delete_all its null)