boost::asio::ip::basic_resolver_iterator doesn't support range-based for loops

[eternaleye]

Adding the following methods is sufficient to resolve the issue:

boost::asio::ip::basic_resolver_iterator<T> begin() {
    return *this;
}
boost::asio::ip::basic_resolver_iterator<T> end() {
    return boost::asio::ip::basic_resolver_iterator<T>();
}

[chriskohlhoff]

Resolver operations now return a range type basic_resolver_results<>.