Add support for DNSCrypt

```
Hi,

i was wondering if it's possible to add support to test DNS servers used with 
DNSCrypt ( https://github.com/jedisct1/dnscrypt-proxy ).

See here for a DNS server list:  
https://github.com/jedisct1/dnscrypt-proxy/blob/master/dnscrypt-resolvers.csv


```

Original issue reported on code.google.com by `Artikelv...@gmail.com` on 4 Jun 2015 at 4:48
