Fix ordering for >9 page docs; allow concurrency; fix filenames

[tris]

No description provided.

[Mikelistowel]

Getting the following error on this:

TypeError Traceback (most recent call last)
in <cell line: 41>()
39 metadata['description'] = soup.find('meta', attrs={'property': 'og:description'})['content']
40
---> 41 metadata['uploaded'] = soup.find('div', attrs={'itemprop': 'datePublished'})['datetime']
42
43 upload_link_soup = soup.find('div', attrs={'class': 'PublisherInfo__name--3j27Y'})

TypeError: 'NoneType' object is not subscriptable

Any advice?