Update py-setuptools to 18.7:

----
18.7
----

* Update dependency on certify.
* Pull Request #160: Improve detection of gui script in
  ``easy_install._adjust_header``.
* Made ``test.test_args`` a non-data property; alternate fix
  for the issue reported in Pull Request #155.
* Issue #453: In ``ez_setup`` bootstrap module, unload all
  ``pkg_resources`` modules following download.
* Pull Request #158: Honor `PEP-488
  <https://www.python.org/dev/peps/pep-0488/>`_ when excluding
  files for namespace packages.
* Issue #419 and Pull Request #144: Add experimental support for
  reading the version info from distutils-installed metadata rather
  than using the version in the filename.

------
18.6.1
------

* Issue #464: Correct regression in invocation of superclass on old-style
  class on Python 2.

----
18.6
----

* Issue #439: When installing entry_point scripts under development,
  omit the version number of the package, allowing any version of the
  package to be used.

(wiz)