Converts values in minutes into values in seconds. The value in minutes
may be entered as a list in any of the following formats: (3 min), or
(3 0); (3 min 30), or (3 30), or (3.5 min); (3 min 30.2), or (3 30.2).
(the letters 'min' may be replaced by simply 'm' or any other non-numeric
character or characters)