Preliminary version of TimeRange.cs

TimeRange_Simple.cs

	public class TimeRange
    {
        private Func<DateTime, DateTime> _delta;

        private TimeRange(Func<DateTime,  DateTime> delta)
        {
            _delta = delta;
        }

        public DateTime Add(DateTime date)
        {
            return _delta(date);
        }

        public static readonly TimeRange OneDay = new TimeRange(dt => dt.AddDays(1);
        public static readonly TimeRange OneYear = new TimeRange(dt => dt.AddYears(1));
        public static readonly TimeRange OneMonth = new TimeRange(dt => dt.AddMonths(1));
    }