#1866: Support pixiv small "_s" thumbnail source rewriting
#1866: Support twitpic source rewriting

* html work page -> full image
* thumbnail -> full image
#1866: Support deviantart source rewriting

* html work page -> full image
* thumbnail -> full image
Potential fix for #2047
remove debug
#2030: Fix regression that borked the -pool: metatag
Merge branch 'master' of https://github.com/r888888888/danbooru