Add switches to setup.py to avoid extraneous and conflicting setuptools files.

Resolves APS-59.
Merge pull request #1 in APS/scipy-roll from bugfix/APS-59-file-conflicts-in-scipy-roll to master

* commit 'b6ad8963236318c50302376ee5509b6b509388c2':
  Add switches to setup.py to avoid extraneous and conflicting setuptools files.