reference API in pysqlite 2.2.1.

Bumbed pysqlite version number to upcoming pysqlite 2.3.1 release.

os.environ (setting envar COLUMNS), which at least caused
test_float_default() to fail if the tests were run more than once.

This repairs the test_optparse -R failures Neal reported on
python-dev.  It also explains some seemingly bizarre test_optparse
failures we saw a couple weeks ago on the buildbots, when
test_optparse failed due to test_file failing to clean up after
itself, and then test_optparse failed in an entirely different
way when regrtest's -w option ran test_optparse a second time.
It's now obvious that make_parser() permanently changing os.environ
was responsible for the second half of that.

Use ctypes.util.find_library to locate the C runtime library
on platforms where is returns useful results.

as reported by Neal on python-dev.

is_term_resized, resize_term and resizeterm. This uses three
separate configure checks (one for each function).

Fix doctest example.
Mention in the tutorial that 'errcheck' is explained in the ref manual.
Use better wording in some places.
Remoce code examples that shouldn't be in the tutorial.
Remove some XXX notices.

is that the wait is failing for some reason.  Use WNOHANG, so we won't
wait until the buildbot kills the test suite.

I haven't been able to reproduce the failure, so I'm not sure if
this will help or not.  Hopefully, this change will cause the test
to fail, rather than hang.  That will be better since we will get
the rest of the test results.  It may also help us debug the real problem.

issues that crop up from time to time, but this change seems to have been
pretty stable (no spurious warnings) for about a week.

Other modules which use threads may require similar use of
threading_setup/threading_cleanup from test_support.

Old url returned status code:301 Moved permanently.

Tkinter variable classes.

(implementation/tests contributed by Sam Ruby)

of this test.  It probably still requires more disk space
than most buildbots have, and in any case is still so
intrusive that if we don't find another way to test this I'm
taking my buildbot offline permanently ;-)

This will hopefully get the buildbots to pass.  Not sure this
test will be feasible or even work.  But everything is red now,
so it can't get much worse.