Add method on Date to parse strings created with date.toString()

People often need to re-parse Dates out of strings created from date.toString().

My particular system's default date.toString() format is "Thu Apr 20 00:27:00 CEST 2006" so I know I can turn a Date into a string and then back into an object using Date.parse('EEE MMM dd HH:mm:ss z yyyy', new Date().toString()).

But breaks when date.toString() changes format, either in a future version of Groovy or when the code moves to another system where date.toString() produces a different format (I'm not clear if this can happen or not).