[Distutils] custom install directory with bdist_wininst

[Jeremy Hylton]

I'd like to give the user control over where the files get installed. 
It looks like distutils installs into site-packages by default, and
there's no way to override it.  The UI shows the destination directory
in a box that looks like it should be editable, but it isn't.

If you run setup.py install, you can pass a --home that affects where
files are installed.  I'm looking for something similar on Windows.

Jeremy