#1 Make DeleteOldThreads Forum-safe

[Rich Bowen]

The DeleteOldThreads code in admin.cgi assumes that all articles are in the same forum. It looks for any article that is old enough, and deletes it,
meaning that all articles in all forums (fora?) would get deleted in that
operation. It is hard to avoid this, since the Thread Table does not store
ForumID information.

There are several possible directions for solutions. One is to use a join to
get only articles in a particular forum. Another one is to reverse the order
of the deletions in that subroutine. A third is make add a ForumID to the
Threads table.