Implemented md5 redirection, 404 for files which don't exist, and redirection from non-trailing slashes to trailing slashes. Made lots of notes for future testing.
Merge branch 'pypi-redirect'

* pypi-redirect:
  Implemented md5 redirection, 404 for files which don't exist, and redirection from non-trailing slashes to trailing slashes. Made lots of notes for future testing.