Add a hidden field that keeps the user on the right page if JS doesn't catch it for the form.
Migrate Dave's new admin_page markup

Bring it over from class.jetpack.php to class.jetpack-admin.php and
stop forwarding the function.
Add a min-height to .page-content

For the modules page, anyways.  Previously, if filtered down to too few
modules, the filters on the right would overflow as they’re positioned
absolutely and can’t push out the float.