I just noticed that there's an ITP for dnscrypt-proxy in the Debian BTS (http://bugs.debian.org/692320). I have submitted a request that this future...
Long ago when Debian contained the "dhcp-client" package (version 2), /etc/dhcp/ was used. When "dhcp3-client" was introduced it used /etc/dhcp3/ so...
The problem could also be with the local NetworkManager-controlled forwarding nameserver. See if disabling it helps. To disable the local forwarding...