2014943715 - Добавлены переменные дат

Для переменных [cdate] и [cdatetime] , доработано смещение даты или времени по этим переменным. пример использования => результат [cdate] => 2019-11-15 [cdate + 1 years] => 2020-11-15 [cdate + 2 months] => 2020-01-15 [cdate + 3 days] => 2019-11-18 [cdate + 4 hours] => 2019-11-15 04:00:00 [cdate + 5 minutes] => 2019-11-15 00:05:00 [cdate + 6 seconds] => 2019-11-15 00:00:06 [cdatetime] => 2019-04-15 15:00:00 [cdatetime + 1 years] => 2020-04-15 15:00:00 [cdatetime + 2 months] => 2019-06-15 15:00:00 [cdatetime + 3 days] => 2019-04-18 15:00:00 [cdatetime + 4 hours] => 2019-04-15 19:00:00 [cdatetime + 5 minutes] => 2019-04-15 15:05:00 [cdatetime + 6 seconds] => 2019-04-15 15:00:06 [cdate] => 2019-11-15 [cdate - 1 years] => 2018-11-15 [cdate - 2 months] => 2019-09-15 [cdate - 3 days] => 2019-11-12 [cdate - 4 hours] => 2019-11-14 20:00:00 [cdate - 5 minutes] => 2019-11-14 23:55:00 [cdate - 6 seconds] => 2019-11-14 23:59:54 [cdatetime] => 2019-04-15 15:00:00 [cdatetime - 1 years] => 2018-04-15 15:00:00 [cdatetime - 2 months] => 2019-02-15 15:00:00 [cdatetime - 3 days] => 2019-04-12 15:00:00 [cdatetime - 4 hours] => 2019-04-15 11:00:00 [cdatetime - 5 minutes] => 2019-04-15 14:55:00 [cdatetime - 6 seconds] => 2019-04-15 14:59:54