Replace query-string syntax with urlconf approach

The query string syntax we're using for paginated content is going to be rather tricky to duplicate with a static set of pages. This changes things so pagination is url-based, which is a lot simpler for generating a static site.

This currently duplicates the default page as /X/page1 - we can work around that if desired, although I'm not sure if the cosmetic issue is that important.

This will also require a fix in the pyconza2013 site templates.