Takes a list and returns an array of permutations of that list.

permute_list

permute_list = (list) ->
    if list.length <= 1
        return [ list ]
    permutations = []
    for first, i in list
        restOfList = list.slice()
        restOfList.splice(i, 1)
        for subperm in permute_list(restOfList)
            permutations.push([ first ].concat(subperm))
    return permutations