dateIncrement
How far into the future/past the calendar navigates when prev/next is executed.
Duration-ish input
Determines how far the calendar will jump when the user presses the prev/next buttons in the headerToolbar or when the prev or next methods are executed.
When using a standard view, it is unnecessary to specify dateIncrement.
When using a Custom View with a specified duration, the duration value will be the default for dateIncrement.