Improved post navigation links

I've made a minor improvement to blogz so that when viewing a single post the navigation links at the bottom of the post show the title of the next/previous post rather than just saying 'Older' or 'Newer'. This was something I had intended to add when I got the database backend working but that is still in limbo. Actually most of the code for the blog output is done, I just can't decide on relatively unimportant details like the serialisation format for the metadata records. The other issue is adds a whole mass of potential complexity to creating posts rather than just editing a file on a shell login. Like an order of magnitue of complexity. It doesn't require this complexity but it enables it.

I made some other minor changes to the stylesheet mostly to do with inline figures (photos and captions), justified the text of posts, and messed about with the About box.