define a more general (and more clearly defined) permlist

[js850]

probably there should be a class Permutations() which organizes possible permutations. a lists of lists is too confusing and not general enough

Permutations() can still take a list of lists as a constructor.

[js850]

should default for permlist be permute all or no permutations? Jake says no permutations. Victor says the opposite

what should permlist is None mean? Jake says no permutations, victor says default behavior.