1.3 on 2.4

I noticed that Twisted 1.3 is now out, with support for Python 2.4.

I'm going to delay the upgrade until Python 2.4.1 final is out. Then I need to make sure CompStrm works with Twisted 1.3. (Some of the integration code may not even be necessary now.)

Meanwhile, I've noticed that I've introduced an error when I was working on qualified names. Introduced a bogus assumption in paint topic, that the topic name would always be present. (Turns out it isn't when a deleted page is selected.) Gotta fix this.