allow adding metatags to recent_tags; don't add unknown non-metatags to recent_tags when we're on a search form
allow adding metatags to recent_tags; don't add unknown non-metatags to recent_tags when we're on a search form

--HG--
branch : moe
extra : convert_revision : svn%3A2d28d66d-8d94-df11-8c86-00306ef368cb/trunk/moe%401010

euank/moebooru-thin,nanaya/moebooru,nanaya/moebooru,euank/moebooru-thin,euank/moebooru-thin,moebooru/moebooru,euank/moebooru-thin,moebooru/moebooru,moebooru/moebooru,moebooru/moebooru,euank/moebooru-thin,nanaya/moebooru,nanaya/moebooru,nanaya/moebooru,moebooru/moebooru