Classes for easily manipulating Dates and times.  While 
      java.util.Date has GDK methods for adding or subtracting days,
      this is not so useful for different durations of time.  
      {@link groovy.time.TimeCategory TimeCategory} creates a simple internal DSL
      for manipulating dates and times in a clean and precise fashion.  
    
  use ( TimeCategory ) {
  	// application on numbers:
  	println 1.minute.from.now
  	println 10.days.ago
  
  	// application on dates
  	def someDate = new Date()
  	println someDate - 3.months 
  }
     
    @see groovy.time.TimeCategory