Changes for clojure.contrib.combinatorics/lex-permutations

tltjr on Sun, 09 Jan 2011
Clojure=> (lex-permutations [1 2 3])
([1 2 3] [1 3 2] [2 1 3] [2 3 1] [3 1 2] [3 2 1])
Clojure=> (lex-permutations [1 1 2])
([1 1 2] [1 2 1] [2 1 1])