Added TrackBack support

Ok, more changes to the news system: I think I have trackback implemented on my site now. I don’t really know whether it’ll work or not, and I haven’t set up a system to actually view any trackbacks I get, but there’s a script that might work. If you try to trackback my site, post a comment to let me know what happens, and I can check the SQL database to see if it actually made any changes. I don’t yet have news post titles implemented, but I’ll work on that later. Post titles will actually appear in several places—the trackback auto-discovery embedded RDF thingy, the RSS feed, and obviously the news page—plus I need to add them in to the editing system. I also changed the RSS feed to use full posts instead of excerpts, I hope that won’t break anything.