A callback that will fire after a selection is made.
function( start, end, jsEvent, view )
start is a Moment indicating the beginning of the selection.
end is a Moment indicating the end of the selection. It is an exclusive value,
so if the selection is all-day, and the last day is a Thursday,
end will be Friday.
You can test if the
end is timed or all-day by calling
select has been triggered via the select method,
jsEvent will be