Fix torrenting issues with one file torrents

All torrent clients do not give a torrent a dedicated subfolder in case the torrent only contains one file. This is giving trouble to several users, see #2252

These updates include the files in the torrents in the info to the renamer (for Deluge, Transmission and uTorrent).

This PR is not well tested and not finished yet.

Current issues:
- directory tagging needs subfolders, so this will go wrong
- rTorrent is not included