strided_range(Difference stride, Rng& rng) : super_t(make_strided_iterator(boost::begin(rng), stride), make_strided_iterator(boost::end(rng), stride)) { }
strided_range(Difference stride, Rng& r) : super_t(make_strided_iterator(begin(r), stride), make_strided_iterator(end(r), stride)) { }