download of single file fails with 404

[blonkm]

the direct download link was actually a trick. I replaced api.schoology with www.schoology and it just happened to work. Unfortunately this was more a vulnerability than a true feature of the site. Now Schoology has fixed the leak and we need to actually download from the api. Since the api redirects to a cdn with a time based token, the redirect cannot be stored and needs to be retrieved for every download.