Thread and forum markers

I have changed the read marker system. It has been the case that threads were marked as read after a visit by a member, but they will now only be marked as read after the member has actually read them, or alternatively double clicked on the forum thread icon to mark the whole forum read.

The latter method is more server intensive, but hopefully the server will be able to cope until we get too big. :)

PS. This will mean initially that members will see lots of unread forums and posts, but it can be easily rectified by double clicking on the forum thread icons on the left hand side to mark them as read. :)

Right . Think I have that