code: public final DateList getDates(final Date periodStart,
                                     final Date periodEnd, final Value value) {
          return getDates(periodStart, periodStart, periodEnd, value, -1);
      }
docs: Returns a list of start dates in the specified period represented by this recur. Any date fields not specified by
  this recur are retained from the period start, and as such you should ensure the period start is initialised
  correctly.
  
  @param periodStart the start of the period
  @param periodEnd   the end of the period
  @param value       the type of dates to generate (i.e. date/date-time)
  @return a list of dates