* Print proper file names to the console when the date could not be
determined
* Skip all directories
* Skip every file that doesn’t have .zip in the file name
Week numbers are obviously the same every year, we need to check the
year as well as the week number to determine if we should keep the
backup file or not.
By default mcMMO keeps the following files:
* All files from the last 24 hours
* Daily backups of the past week
* Weekly backups of the past months
Adds #1574
