This isn't really a mod: these are just added into your template.
The 'top' links are in the bundled templates. If you're using a custom template, I suppose it's possible they were removed. Just matter of setting an anchor at page/content top (if not already there) and links to it.
A 'bottom' link, I don't know why you would have the skip the pages content (why are they on the page anyways then?) but it's the same thing. Add an anchor in the footer and target from a link in the head.