Handle urllib's renaming for Python 3.0:

* Deprecate urllib.urlopen() in favor of urllib2.urlopen() for 3.0.
* Update docs to mention split/rename of the module and deprecation of
  urlopen().

Changes to lib2to3 are in a separate commit. Work is for issue #2885.
diff --git a/Lib/test/test_urllibnet.py b/Lib/test/test_urllibnet.py
index 5e225ee..0404b77 100644
--- a/Lib/test/test_urllibnet.py
+++ b/Lib/test/test_urllibnet.py
@@ -182,9 +182,13 @@
 
 def test_main():
     test_support.requires('network')
-    test_support.run_unittest(URLTimeoutTest,
-                              urlopenNetworkTests,
-                              urlretrieveNetworkTests)
+    from warnings import filterwarnings
+    with test_support.catch_warning(record=False):
+        filterwarnings('ignore', '.*urllib\.urlopen.*Python 3.0',
+                        DeprecationWarning)
+        test_support.run_unittest(URLTimeoutTest,
+                                  urlopenNetworkTests,
+                                  urlretrieveNetworkTests)
 
 if __name__ == "__main__":
     test_main()