Take torrent as the default argument without requiring a flag.
Take torrent as the default argument without requiring a flag.

Better usage message.

Simplify code.

rakoo/rakoshare,zyxar/taipei,ansonwzj/CPSC416Taipei,beni55/Taipei-Torrent,FlexibleBroadband/Taipei-Torrent,Dataman-Cloud/Taipei-Torrent,rakoo/rakoshare,nictuku/Taipei-Torrent,ansonwzj/CPSC416Taipei,nictuku/Taipei-Torrent,Dataman-Cloud/Taipei-Torrent,beni55/Taipei-Torrent,FlexibleBroadband/Taipei-Torrent