Unmaintained [DBTech] DragonByte SEO URLs to XenForo 2 1.0.0a3

This update adds support for Attachment URLs rewritten using DragonByte SEO, as well as fixing a few problems with "Go To Post" and "ShowPost" URLs.

These fixes are not applied retroactively, so if you need these fixes you will need to re-import your DragonByte SEO URLs.

If you have not come across any reports of 404 errors with your old URLs, you probably don't need this update.

Fix: Fixed an issue where the urlFormats.php file used as a lookup table could generate empty regular expressions, which causes issues when resolving old URLs.

If you were affected by this issue, re-do the "DragonByte Tech: SEO to DragonByte Redirect" import step after upgrading.