Scene loading fixes

module.jai

@@ -38,6 +38,7 @@ Engine_Core :: struct {
     procs: struct {
        on_scene_loaded: (*Scene, Engine_Mode);
        on_pre_scene_loaded: (*Scene, Engine_Mode);
+       on_pre_scene_unloaded: (*Scene);
        on_trigger_enter: (*Entity, *Entity);
        on_trigger_exit: (*Entity, *Entity);
     }