[Catalog-sig] Automatic redirects for normalized names

["Martin v. Löwis"]

Now that PyPI is free of name collisions with respect to
the (setuptools) normalized_name, the "simple" API offers
redirects in cases where a name was misspelled.

E.g. accessing

http://pypi.python.org/simple/pyxml

will redirect to

http://pypi.python.org/simple/PyXML

This should remove the need to download the entire simple
index in setuptools, in most cases.

Regards,
Martin