The pydoc module currently only outputs ASCII and
crashes with UnicodeEncodeError when printing a unicode
string (in contexts where it prints the str rather than
a repr, e.g. docstrings or variables like
`__credits__`).  The most ironic example of it is that
since patch 1009389 was committed, ``pydoc.py pydoc``
crashes on its own `__credits__`!

This patch changes pydoc help functions to return
unicode strings only when needed; it returns ASCII
strings if all characters are from ASCII.  Therefore
there should be no compatibility problems.

For output, all pager functions were changed to encode
to the locale's preferred encoding and HTML output was
changed to always use UTF-8.

cgitb.py, DocXMLRPCServer.py and/or
SimpleXMLRPCServer.py seems to rely on pydoc to some
degree.  I didn't touch them, so they might still be
broken in this respect.