init
Merge pull request #1 from thomaszhwang/previous_next_dmy

init
improve is current day valid
Merge pull request #2 from thomaszhwang/improve_is_current_day_valid

improve is current day valid
add new functions for previous/next dmy
merge
ierge branch 'previous_next_dmy'
delete
Merge pull request #4 from yliu1019/delete_file

delete