Fix: Correct Windows build docs.

     - Windows MSVC requires the 2008 version:
       - Per http://docs.python.org/2/extending/windows.html, Python extensions must be compiled with the same compiler used to compile Python.
       - Per http://docs.python.org/devguide/setup.html#windows, it's MSVC 2008.
     - I have both VS 2008 and VS 2010 on my PC. Leaving off the -G option causes it to select VS 2010.