Re-re-rehash of the rejected #74, #75 and #76

[graingert]

Re-re-rehash of the rejected #74, #75 and #76

Includes these changes:

• Add a link from PyPI direct to the Github repository, so people can find the changelog. It's really annoying when upgrading to have to resort to Google-sleuthing to find the changelog to see if there are any breaking changes.
• Revert back to only using distutils (pip replaces this with setuptools transparently when building wheels)
• Include releasing as a universal wheel to speed up users' installs. Run ./dist.sh to distribute your legacy sdist and your wheels

[lkorth]

Thanks for the PR, we're going to use #76 to support wheels.