Message 68005 - Python tracker

This is the most difficult part of issue1342:
"""
On Windows, don't use the FileSystemEncoding on Windows for sys.path items.
Instead, it should use the wide API to perform all system calls. Py3k
shouldn't ever use the file system encoding for anything on Windows.
"""

This imply to rewrite all functions in import.c, and replace all char*
arguments with unicode variables.