/**
* Compare the reciever with another date. If receiver is the same date as the
* date it returns 0 if receiver is before the dat it returns 1 and if it's after the date
* it returns -1
*
* @param KDate $date
* @return int
*/
public function compare(KDate $date)
{
$thisTimestamp = $this->getTimestamp();
$dateTimestamp = $date->getTimestamp();
return $thisTimestamp - $dateTimestamp;
}