Adds sort and filter buttons to Gelbooru search: by score, random, period, rating and size. No tag syntax needed.
Per
Sort and filter Gelbooru searches with buttons, without tags like sort:score or -rating:explicit.
The buttons sit under the search box. Pick an option and the results update.
The first period lookup takes a few seconds, then it's cached. Requests go to gelbooru.com only.
