Add binary search based weighted choice

[ccssmnn]

GA and ACO use the weightedChoice method. Currently it uses a linear search strategy with O(N) performance. However a binary search with O(log(N)) could be used whenever multiple selections from the same weights are made.

I found a python implementation here

def prepare_binary_search(weights):
    # Computing the running totals takes O(N) time
    running_totals = list(itertools.accumulate(weights))
        
    def weighted_random():
        target_distance = random()*running_totals[-1]
        low, high = 0, len(weights)
        while low < high:
            mid = int((low + high) / 2)
            distance = running_totals[mid]
            if distance < target_distance:
                low = mid + 1
            elif distance > target_distance:
                high = mid
            else:
                return mid
        return low

    return weighted_random