Updated functionality in clothes and skin repos

[joepal]

I've implemented a change which I think will solve the problems with conflicting and unupdatable files in clothes and skin uploads. It should now be possible to have the same filename in multiple clothes item (even inside one clothes item, although that's probably a bad idea for other reasons).

The change is not retroactive, so it does not fix a post which has broken links. However, if you edit/update the post now, it should (probably) solve the issues.

Worst case scenario, if you still can't fix a broken post: delete it and create a new one with the same title and upload your files there instead. That should clear out all broken file links.