update URL for TorDNSEL

https://metrics.torproject.org/collector.html#exit-lists

links to https://dist.torproject.org/tordnsel/ which has a version from 2007

lets replace the url with (from 2016-05-04): https://gitweb.torproject.org/tordnsel.git/tree/README

link Tor check to https://gitweb.torproject.org/check.git