Preload month data by delegate

[vdvleon]

It would be a very usefull functionality to know which months are (about to be) visible. This way I can load data for the day cells. It would be usefull to have delegate functions like:

func simpleCalendarViewController(controller: PDTSimpleCalendarViewController!, monthCanAppear date: NSDate!)
func simpleCalendarViewController(controller: PDTSimpleCalendarViewController!, monthDidAppear date: NSDate!)
func simpleCalendarViewController(controller: PDTSimpleCalendarViewController!, monthDidDisappear date: NSDate!)

Here date would be the first of the month. Two ints (year and month) could work aswell.

A setting could determine how many months 'can appear' when scrolling (for example preload 2 months who are not in visible yet).

This way I can preload additional data about the dates in that month (in my case availibility information for a reservation system).

I can imagine other people would like this feature aswell.