osutil: proxy through util (and platform) modules (API)
See the previous commit for why. Marked as API change since osutil.listdir()
seems widely used in third-party extensions.
The win32mbcs extension is updated to wrap both util. and windows. aliases.
# name space package to host third party extensions
from __future__ import absolute_import
import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)