Add a final permutation step to the tuple hash function.

Prevents a collision pattern that occurs with nested tuples.
(Yitz Gale provided code that repeatably demonstrated the weakness.)
diff --git a/Misc/ACKS b/Misc/ACKS
index 6d3ad2c..480a1ec 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -190,6 +190,7 @@
 Peter Funk
 Geoff Furnish
 Lele Gaifax
+Yitzchak Gale
 Raymund Galvin
 Nitin Ganatra
 Fred Gansevles