[Catalog-sig] simple package index has links back into the human interface

["Martin v. Löwis"]

> Martin, can you filter links like this out of the simple output?

I had already filtered out cheeseshop.python.org/pypi and
pypi.python.org/pypi, and now also filter www.python.org/pypi.

So these should be gone now. Please let me know if there are
further problems.

Regards,
Martin