Log Message:
Update to 13.0.1:

13.0.1 (2015-05-22)
~~~~~~~~~~~~~~~~~~~

* Upgrade pip to 7.0.1

13.0.0 (2015-05-21)
~~~~~~~~~~~~~~~~~~~

* Automatically install wheel when creating a new virutalenv. This can be
  disabled by using the ``--no-wheel`` option.

* Don't trust the current directory as a location to discover files to install
  packages from.

* Upgrade setuptools to 16.0.

* Upgrade pip to 7.0.0.