Date repeater.
WEEKEND_SECONDS
(2 * 24 * 60 * 60)
$now :
$currentWeekStart :
width()
returns the width (in seconds or months) of this repeatable.
next( $pointer = 'future')
returns the next occurance of this repeatable.
this( $pointer = 'future')
__toString()
offset( $span, $amount, $pointer)