add tests for columnHead option
add tests for columnHead option

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