Add List#addAll(int index, Collection c) based Factory method

[axkr]

In CombinatoricsVector

    public CombinatoricsVector(int index, Collection<? extends T> vector) {
        _vector = new ArrayList<T>(vector.size()-index);
        _vector.addAll(index, vector);
    }

In Factory

    public static <T> ICombinatoricsVector<T> createVector(int index,
            Collection<? extends T> collection) {
        return new CombinatoricsVector<T>(index, collection);
    }