ensure that it will be found regardless of the shell PATH. This ensures
that multiprocessing.cpu_count works on default installs of MacOSX.

Emphasize the ['x', 'y'] option for listing field names.  Remove PS2 prompts to make the examples cut-and-pasteable.

longer fails if zlib is not installed. Instead, the zipfile.ZIP_STORED
compression is used to create the ZipFile. Patch by Natalia B. Bidart.

in the _posixsubprocess C extension module it would unintentionally close the fds and raise
an error.

The fix is to charset.py, which was not doing the encoding to the
correct output character set when doing a body_encode for either
the shift-jis or euc-jp charsets.  There's also a fix for handling
a bytes input in encoders.py.

Patch by Michael Henry, comment changes by me.

when test_subprocess was run.