WhereLoot

- New filter bar below spec selector with secondary stats. Click one stat to see all gear with that stat, or click two for an exact combo.
- When stat filter matches nothing, says "No items match these stats" instead of the generic message.
NOTE: Trinkets are interesting, and my brain is hurting. Let's just pretend trinkets don't work for the stats filters. I'll come back to this tmrw. 

- When a boss drops multiple matching items for your filter, the row expands
- Added dark backdrop behind the stat and slot bars for better text contrast

- Fixed world boss loot not appearing in some cases.
- Fixed Adventure Guide button not toggling WhereLoot off when already open.
- various internal cleanup and performance improvements.

Thank you to everyone on r/wow for the lovely feedback and requests. Was kinda reluctant to share what's just a fun project to a possibly heavily critiquing crowd but the data yall are providing is making this even more fun ^.^