deduplicate logic
create more producer goroutines (torrent lib does limiting internally amount of consumers/disk-readers/hashers by 2, and it's enough because we can verify multiple files in parallel)
move flag from "downloader torrent_hashes --verify" to "downloader --verify"
deduplicate logic create more producer goroutines (torrent lib does limiting internally amount of consumers/disk-readers/hashers by 2, and it's enough because we can verify multiple files in parallel) move flag from "downloader torrent_hashes --verify" to "downloader --verify"