bug #325: Fix print output in @at_cleanup functions not appearing in node console

[scroix]

As described in #325 print messages aren't redirected to the Nodel console during clean-up.

The issue appears to be that when the cleanup function(s) are triggered, the Python interpreter's system state isn't set correctly, and subsequently sys.stdout and sys.stderr redirects aren't established.

This PR does the most obvious thing and (1) resets the interpreter's state and (2) assigns the output streams to the node's console before running through the list of clean-up functions provided by a node.