Running alitv.pl twice with overwrite results in an error #150

When I run alitv.pl test.yml --overwrite repeatedly it works twice and then fails. The reason is that the first time the test.map file does not exist so no need to overwrite at all. The second time a test.map file exists and is backuped to test.map.bak and then overwritten. In all consecutive runs both the test.map and test.map.bak files exist and AliTV refuses to overwrite test.map.bak.

This behavior is not intuitive. For me setting the --overwrite flag explicitly means "please overwrite all existing, conflicting files". Therefore I would not even expect a .bak file to be created. And if it is created I wont expect it to cause consecutive runs to fail. I'd vote for not creating a backup file at all and this problem should be solved.