For 1.6.0a13

I'd been using the now-removed option of --no-overwrite in a script. It seems the new equivalent is --skip-existing-tags. However, using it will still get new tags applied. On a lark, I tried using --no-skip-existing-tags and that did what I wanted:

Already has Comic Rack tags. Not overwriting.

It seems the logic is reversed from the wording of the option.