Fix: #333 Delete archived files in correct order

Fix for deleting archived files based on date in correct order (oldest
should be deleted, not random).
Merge remote-tracking branch 'origin/master' into issue333
Fixed #281: Don't create empty batches when event list is empty
Test for #281
Merge pull request #347 from robertvazan/master

Fixed #281: Don't create empty batches when event list is empty
Merge pull request #346 from cvanbergen/issue333

Fix: #333 Delete archived files in correct order