Fixed issue #9171 : Unable to subscribe to event
Dev : Target not anymore needed for auth plugins events, every auth plugin knows if he has to process event
Dev : This way, auth events (i.e. afterLogout) can be processed also by other plugins
Dev : Method afterLoginFormSubmit can be in parent class (preventing code duplication)
Merge pull request #260 from Aestu/no_target_for_auth_plugins_4

Fixed issue #9171 : Unable to subscribe to event