When the URL does not end with an slash, the downloaded file becomes index_no_slash.html.
But the converted local links are wrong, because url.join() is called, and since the URL does not end with an slash, it strips away the last folder, thinking it is a file.
I made a hackish fix here: https://github.com/raphCode/suckit/tree/hack_url_fix
Not sure if you want to merge, feel like a mess.