[Catalog-sig] Changing cheeseshop.python.org to pypi.python.org

["Martin v. Löwis"]

> So why not change the name to "Python Project Index"? The abbreviation
> stays the same...

Because I'm uncertain how people will react to it. The unabbreviated
name really doesn't matter that much, except for Google searches
perhaps. If "Project Index" gets a clear preference over "Package
Index", we can try that; if people are likely to object to it also,
nothing is gained.

Regards,
Martin