This removes the old ez_setup.py, which was used ages ago to install

setuptools when missing. This isn't needed anymore, and given that

ez_setup.py has syntax errors on Python 3, it does more harm than

good.
The contrib/internal/release.py has been removed as well. We haven't

used it in years, since we now have our own centralized release

infrastructure.
These files are removed from MANIFEST.in. Newer packaging/build files

in the source tree have been added, ensuring they're in the source

distribution.

Built the source distribution. Saw that it contained all the files that

I expected to see, and didn't contain anything else.
Built egg and wheel packages.