[docs] [issue20265] Bring Windows docs up to date

Kathleen Weaver added the comment: I think I've incorporated everything wanted, and simplified things. Instead of going through how to change environment variables, I've pointed to another source. I've added the VS tools. ---------- Added file: http://bugs.python.org/file34475/kweaver.patch _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue20265> _______________________________________