Refresh forum threads every 30s
When looking at a forum thread page, it would be nice to have the discussion update itself every 30 seconds or so.
The idea is just to show new comments. For now, we don't care about modifications of previous posts. Just the new ones.
This is a bit difficult, however, considering the fact that the replies can be idented (can be children of another reply) and that there are several possible view for the forum, but it should be possible to find a nice way to do it.
To avoid loading the server too much, this refresh should be a small AJAX call that requests all new posts since the last refresh, based on the forum_post.post_date field (saved in UTC).