Make gallery open at the image we've scrolled to.

Also fixes a bug with spoilered image file names.
Merge branch '1.8.9.x'
ignore quote links inside [code] tags; they shoudn't be there and cause bugs
Merge branch '1.8.9.x'
move some stuff out of Gallery.cb
don't scroll to post when initially opening gallery
fix bug in opening gallery to current image when image was expanded
Revert "don't scroll to post when initially opening gallery"

This reverts commit 432f1c4b36b16e121cdb416890a12a9f0db6e2f7.
this seems to fix the anomalous scrolling in Firefox
remove unused function Header.initReady
Partial: unread counter in Thread Watcher
bugfixes for thread watcher count
better fix: move unread count back inside link
adding thread should check unread count
make unread count in thread watcher optional
remove unread count from dead threads
add thread watcher refresh button
don't try to embed iframes/objects from HTTP-only services
make expanded images {clear: left} so they have room to expand
make refresh button spin