added __all__ lists to a number of Python modules

added test script and expected output file as well
this closes patch 103297.
__all__ attributes will be added to other modules without first submitting
a patch, just adding the necessary line to the test script to verify
more-or-less correct implementation.

Lib/UserDict.py

@@ -1,5 +1,7 @@
 """A more or less complete user-defined wrapper around dictionary objects."""
 
+__all__ = ["UserDict"]
+
 class UserDict:
     def __init__(self, dict=None):
         self.data = {}