Add web seeds to magnet links.

[Sartre]

Currrently, web seeds in torrents aren't included in the generated magnet link. They are added with the %ws delimiter.

eg.  &ws=http%3a%2f%2fwww.ex.ua%2fget%2f279520193


Also, get rid of defunct trackers like open.demonii.com and exodus.desync.com