Rename to Dm_Energy
Rename to Dm_Power
Rename to Dt_Miesiac
Rename to Dt_Rok
Rename to Dt_RapPierwszy
Rename to Dt_RapDrugi
Add spring_dst_day
Check spring_dst_day
Check spring_dst_day
Add day_in_last_week_of_long_month
Check day in last week of month
Use last 7 days of 31-day month
Add is_ymd_sunday
Implement is_ymd_sunday for real
Use is_ymd_sunday
Simplify day_in_last_week_of_long_month
Use day_in_last_week_of_long_month
Add month_dst_day
Use month_dst_day
Add report_missing_days