memory leaks in PyAES

[Paul Rubin]

If anyone cares, I found two bad memory leaks in PyAES 1.0.
Unfortunately, no one seems to be maintaining it any more.
I currently have limited net access so I can't conveniently
upload a patch.  But I posted a description of the problem
on the pyAES message board:

  http://sourceforge.net/forum/forum.php?thread_id=142079&forum_id=56376

it should be enough to let someone else quickly make the appropriate fix.