allow using window.history.replaceState if it's available, to avoid spamming the browser history for every image change
allow using window.history.replaceState if it's available, to avoid spamming the browser history for every image change

--HG--
branch : moe
extra : convert_revision : svn%3A2d28d66d-8d94-df11-8c86-00306ef368cb/trunk/moe%401076

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