LunarMonth constructor
Implementation
LunarMonth(int year, int month, int dayCount, double firstJulianDay, int index) {
_year = year;
_month = month;
_dayCount = dayCount;
_firstJulianDay = firstJulianDay;
_index = index;
_zhiIndex = (index - 1 + LunarUtil.BASE_MONTH_ZHI_INDEX) % 12;
}