Add threading.Barrier

than 1.  This matches the pure Python implementation in _pyio and should
fix a couple of failures on the NetBSD buildbot.

xml.sax.saxutils.XMLGenerator as being bound to
http://www.w3.org/XML/1998/namespace.  Patch by Troy J. Farrell.

doc section under frameworks.  Also fixed a couple of markup issues
that affected TOC rendering.

 * Windows always uses mbcs
 * Mac OS X always uses utf-8

As suggested by Antoine, it's better to patch only test_pep277 than the
unittest module.

narrow/wide unicode build.

keep a local copy of the fileystem encoding, instead of calling
sys.getfilesystemencoding() each time.

The filesystem encoding is now constant.

except when configured --with-pydebug.

Emit this warning from the GC shutdown procedure, rather than just printing to stderr.