error when a named pipe is encountered, rather than blocking infinitely.

Based off of subversion r69 from http://code.google.com/p/ipaddr-py/

This code is 2to3 safe, I'll merge it into py3k later this afternoon.

All changes are mirrored to the underlying os.environ dict, but rolled back
on exit from the with block.

"<local>" macro as the only entry, this function bypasses any host name that
does not contain a period.

more cleanup, but I don't know now to kill turtles.  Especially
unexpected ones... ;)

(Backport of r72109 from py3k.)

  the order that backends for the dbm extension are checked.

  the order that backends for the dbm extension are checked.

process instead of throwing errors for anything not in an explicit
skip list.  This is per this spec: http://www.cnpbagwell.com/aiff-c.txt.
Spec reference and test sound file provided by Santiago Peresón, fix
based on patch by Hiroaki Kawai.

instead of mipsel)

enabling doctests that Sphinx can run, and fixing and disabling tests that
Sphinx can't run.  I hand checked every test not now marked as a doctest,
and all except the two that have open bug reports against them now work,
at least on Linux/trunk. (I did not look at the last example at all since
there was already an open bug).  I did not read the whole document with
an editor's eye, but I did fix a few things I noticed while working on
the tests.

string is already in normalized form, by performing a quick check beforehand.
Original patch by Rauli Ruohonen.

at once could hit the recursion limit if the mimetypes database hadn't been
initialized before.

Issue #5793: rationalize isdigit / isalpha / tolower, etc. Will port to py3k. Should fix Windows buildbot errors.

works when an exception gets to the interactive prompt, and update the
examples after testing.  The last one is now a valid Sphinx doctest,
but of the preceding two one can't be made a doctest and the other one
I'm postponing to 3.x because sphinx handles doctests as Unicode strings
and that makes the 2.x output confusing.

should clutter the docs as possible.  Part 1: stuff that gets merged to Py3k.