Quite a few fixes to make the library and test suite more robust when

cPickle cannot be imported.  This was necessary because my last mass
checkin broke cPickle and I don't feel like debugging it right now;
but it seems a good idea in general not to require cPickle when
pickle.py is also there.  A few unrelated fixes for issues while
debigging various test failures.

setup.py: disable building of cPickle until I've fixed it

Objects/...

  genobject.c: disallow raising string exceptions

Lib/...

  Cookie.py: fix doctest not to fail if cPickle is missing
  ctypes/macholib/dyld.py: fix relative imports
  sqlite3/__init__.py: fix relative import
  xml/dom/__init__.py: fix relative import

Lib/test/...

  regrtest.py: reduce list of skipped items on darwin

  test_generators.py: don't test string exceptions; test throw() errors
  test_traceback.py: don't test string exceptions

  pickletester.py: don't fail if cPickle is missing
  test_datetime.py: don't fail if cPickle is missing
  test_descr.py: don't fail if cPickle is missing (still some other failures)
  test_exceptions.py: don't fail if cPickle is missing
  test_re.py: don't fail if cPickle is missing

  test_array.py: use pickle, not cPickle
  test_bool.py: don't fail if cPickle is missing
  test_deque.py: use pickle, not cPickle
  test_logging.py: use pickle, not cPickle

Lib/test/regrtest.py

@@ -1033,25 +1033,19 @@ _expectations = {
         """,
     'darwin':
         """
-        test__locale
         test_al
         test_bsddb
         test_bsddb3
         test_cd
         test_cl
-        test_curses
         test_gdbm
         test_gl
         test_imgfile
         test_largefile
         test_linuxaudiodev
         test_locale
-        test_minidom
         test_nis
-        test_ntpath
         test_ossaudiodev
-        test_poll
-        test_sqlite
         test_startfile
         test_sunaudiodev
         """,