Release DateMath B0.1.7

Thanks to user feedback, both by mail and on the forums:

Changed Slovenian (SI) currency from SIT to EUR in Iso4217Currency enum.
Addded LUNAR_MONTHLY value to the Frequency enum.
Added test for monthly schedules generated on the 31st of each month.
Fixed bug in schedule generator where monthly schedules generated with reference to the 31st of each month are generated incorrectly.
Changed the HolidayCalendar abstract class so that concrete implementations can just implement isWeekend and isHoliday independently and adjustments will still work.