First merge from the trunk straight into the py3k branch. I'm not

using the message generated by svnmerge, because it contains a lot of
stuff about the Doc tree, which I'm not merging this time due to the
way the Doc tree was initially added.  I am however adding roman.py
which was added later to Doc/tools.  I'll try to diff the two Doc
trees separately to see if there's stuff I missed.

Lib/test/test_support.py

@@ -261,14 +261,6 @@ def open_urlresource(url):
     fn, _ = urllib.urlretrieve(url, filename)
     return open(fn)
 
-@contextlib.contextmanager
-def guard_warnings_filter():
-    """Guard the warnings filter from being permanently changed."""
-    original_filters = warnings.filters[:]
-    try:
-        yield
-    finally:
-        warnings.filters = original_filters
 
 class WarningMessage(object):
     "Holds the result of the latest showwarning() call"
@@ -292,7 +284,7 @@ def catch_warning():
 
     Use like this:
 
-        with catch_warning as w:
+        with catch_warning() as w:
             warnings.warn("foo")
             assert str(w.message) == "foo"
     """