Method to force fresh rerendering of view

Originally reported on Google Code with ID 2444

There doesn't seem to be a way to ensure that the dayRender is re-run on all days. I've
asked a StackOverflow question <http://stackoverflow.com/questions/28401749/redrawing-a-fullcalendar-so-that-the-dayrender-callback-is-called>
that highlights how `render` doesn't always do this. The workaround of recreating the
entire calendar produces visual issues.

This is useful in my case where I am trying to change the appearance of days on the
fly (applying arbitrary CSS and HTML changes to day cells). I need to be able to refresh
the table (and thus calling `dayRender` again) when the source I'm watching changes
(which is the same source that `dayRender` uses to determine how to render each day).

Reported by [e-mail] on 2015-02-17 18:48:18

Imported with 3 stars.

[arshaw]

there’s a rerenderEvents method

[shenlong]

Meantime, I found that I can refresh if I can the previous and next view.

$('#calendar').fullCalendar('prev');
$('#calendar').fullCalendar('next');

Do take note on performance issue if you have events in the calendar.