Log Message:
Update py-virtualenv to 14.0.5:

14.0.5 (2016-02-01)
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* Homogenize drive letter casing for both prefixes and filenames. :issue:`858`

14.0.4 (2016-01-31)
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* Upgrade setuptools to 19.6.2

* Revert ac4ea65; only correct drive letter case.
  Fixes :issue:`856`, :issue:`815`