Improve the default torrents

The default torrents could be a lot better:

• Torrent should all be named properly (so we can remove the hardcoded displayName property in config.json that overrides the torrent's actual name)
• Each torrent should have subtitles in as many languages as is available.
• Remove garbage files (Cosmos Laundromat has .sqlite, .xml, and .ogv files that can go)
• Add poster.jpg images to all torrents (to demonstrate this best practice to users)