Added process_children callback methods to StandingEvent to handle CRUD functionality for child records (e.g. delinquent_loss)
Updated .update_attributes method references to current .update syntax.
Removed Raid.secondary_stage method (deprecated)
Removed most outside processing within Standing.retire & Standing.resume, into callback actions of StandingEvent model.
Added StandingEvent.update test.
Added StandingEvent.destroy test.