Changes

* http://exploit-exercises.com/

** Nebula: <pre>magnet:?xt=urn:btih:f64d0e33e596cad196e3be22990b39dae51e48b7&dn=Nebula%5Fexploit-exercises-nebula-4.ova&tr=udp%3A%2F%2Ftracker.ccc.se%3A80&tr=http%3A%2F%2Ftracker.ccc.de%2Fannounce&tr=udp%3A%2F%2Ftracker.publicbt.com%3A80&tr=http%3A%2F%2Ftracker.publicbt.com%2Fannounce&tr=udp%3A%2F%2Ftracker.openbittorrent.com%3A80&tr=http%3A%2F%2Ftracker.openbittorrent.com%2Fannounce</pre>

* https://stripe-ctf.com

* http://io.smashthestack.org