addresses #436: Updating MANIFEST.in does not correctly update the package sdist creates

Docs: notes on setup.cfg and ez_setup

(see # 1006)

Fixes for Visual Studio 2017

- VCRuntimeRedist new path since VS2017.
- Use always last Windows SDK and UCRT SDK when more than one version are available.
- Minors docstrings changes.

Tested with "Visual Studio 2017 Community" and "Visual Studio Build Tools 2017".

Fixes #999: support python_requires and py_modules in configuration files

Although bootstrap.py is installing the deps, it removes them as well, so doc builds still require build deps.

Make sure bootstrap finishes before continuing, and ensure that jaraco.packaging.sphinx is run before rst.linker.