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/atexit.py

@@ -5,6 +5,8 @@ upon normal program termination.
 One public function, register, is defined.
 """
 
+__all__ = ["register"]
+
 _exithandlers = []
 def _run_exitfuncs():
     """run any registered exit functions