Generate static link index when building wheels

[Ian Cordasco]

In version 6, pip has stopped caching index pages if they do not provide the proper cache control headers. mirror.rackspace.com generates our indices dynamically and will not serve cache control headers unless we generate a static index file with the appropriate links. With this addition, installation times with pip 6 should begin to rival those with pip 1.5.6 if not exceed them.