Fix #1643 - Upgrade six to 1.6.1
Upgrade pip._vendor.distlib to 0.1.8
Upgrade bundled pkg_resources and _markerlib to 3.4.4
Merge pull request #1750 from dstufft/upgrade-distlib

Upgrade pip._vendor.distlib to 0.1.8
Use a smaller repository in the tests for speed.

Refs #1721
Merge pull request #1691 from dstufft/upgrade-six

Fix #1643 - Upgrade six to 1.6.1
Merge pull request #1752 from dstufft/upgrade-setuptools

Upgrade bundled pkg_resources and _markerlib to 3.4.4
Merge pull request #1754 from alex/patch-3

Use a smaller repository in the tests for speed.
Upgrade colorama to 0.3.1