Put header and footer on their places

Hi again, @andredias! I have written sample testcase (which fails) for a problem that I have faced with. Plase take a look. In the original **rst2html** utility when you use `header` or `footer` directive they are placed in the top and the bottom of generated page, respectively, which is right behaviour IMO. But in **rst2html5** header and footer both placed in the top of a page, which is wrong.

Any thoughs how to fix that?