filtercollection: adding fix to change_event (only fires if model blongs to collection). also, adding in diff_events option for refresh function (fires add/remove events for each model added/removed after refresh.
filtercollection: adding fix to change_event (only fires if model blongs to collection). also, adding in diff_events option for refresh function (fires add/remove events for each model added/removed after refresh.

lyonbros/composer.js,lyonbros/composer.js,lyonbros/composer.js