requested to merge a002527/climix:feature_add_tests_first-last_occurrences into main
- Unit tests has been added to FirsOccurence and LastOccurrence index functions.
- FirstOccurrence returned 0 for the first day this is now changed to 1. This means that "something" that occurred on 1 Jan will give output: 1 [days]. This also matches the output from Last Occurrence.