[Python-3000] Removing windows 95 specific code

[Amaury Forgeot d'Arc]

Hello,

Python 3.0 has already dropped support for Windows 9x in several
places, and is now expected to only work with the NT family.

I propose to remove the remaining code specific to windows 9x/ME.

This includes:
- Py_WIN_WIDE_FILENAMES is always defined
- when given a unicode string, try to always use the wide version of
the win32 api.
- w9xpopen will disappear

Are there objections?
Windows CE uses unicode, and is supposed to survive this change.

Another question:
I noticed that open() and other functions accept bytes objects. Is it intended?
There is no test for this in the test suite. I will add some when I
know what is needed.

Another question #2:
on posix platforms, os.path.supports_unicode_filenames is False.
So far, this variable is only used to run test_pep277.py or not. Did
we make some progress on this topic since the unicode-everywhere
rewrite? (see also http://bugs.python.org/issue767645 )

Cheers,

-- 
Amaury Forgeot d'Arc