Fix type definition for eventAllow callback.
Fix type definition for eventAllow callback.

fullcalendar/fullcalendar,arshaw/fullcalendar,fullcalendar/fullcalendar,oleg-babintsev/fullcalendar,arshaw/fullcalendar,fullcalendar/fullcalendar,oleg-babintsev/fullcalendar,oleg-babintsev/fullcalendar,fullcalendar/fullcalendar,arshaw/fullcalendar,arshaw/fullcalendar