Fix double decode of file url

[antonsoroko]

1. Remove DecodeFileURL from TorrentFS.Open()

URL is already decoded (you can print it to check, i guess it is decoded by library, although i have not found this in docs, but it is definitely already decoded), so if raw file path has special characters - then it will be unnecessarily "decoded" again and file will not be found.

e.g. if path has %7C in name. (it supposed to be | but was encoded by publishing software, i guess)

example of such strange file path:
https://animaunt.org/13543-napadenie-odinochki-na-inoy-mir.html
https://animaunt.org/13859-proschay-zhizn-drakona-zdravstvuy-zhizn-cheloveka.html
Прощай, жизнь дракона. Здравствуй, жизнь человека %7C Sayounara Ryuusei, Konnichiwa Jinsei
Нападение одиночки на иной мир %7C Hitoribocchi no Isekai Kouryaku

i tested my change on 16 different torrents - all ok.

2. Add EncodeFileURL for Audio file
   like it was done for subtitles earlier escape path for subtitles #52
   and how it was done for video from the beggining.

3. Add small debug message to TorrentFile.Download() to see what headers we add when we download .torrent file.