Geoffrey Swift's βlog - HTTP Redirect for blog category tweak

I made the site a bit cleaner and removed some repetition in the content. The "updates" and "podcasts" categories each already had their own dedicated php page, to be directly accessed from the main menu. When the XPath query passed to the generic blog page would result in either of these categories, an HTTP redirect automagically sends you there instead. This then ties the blog filtering/navigation into the overall site navigation. Currently this is hardcoded, so I may look into a more generic mechanism to facilitate the addition of further categories into the main menu. Either way the XPath in the query string for blog.php generated by the XSL will work, as it did before.