Additions [furaffinity] add artist_url metadata field (#821) [redgifs] add user and search extractors (#724) Changes [deviantart] extend extra option; also search journals for sta.sh links (#712) [twitter] rewrite; use new interface (#806, #740) Fixes [kissmanga] work around CAPTCHAs (#818) [nhentai] fix extraction (#819) [webtoons] generalize comic extraction code (#820)
