[Request]Force fallback DNS for user-selected proxy app

In a network situation when Simple DNSCrypt can't work without a proxy, if the proxy needs a working DNS to work, it creates a "Chicken or the egg" problem and stops any app from querying DNS. AFAIK popular proxy solutions in China like Shadowsocks and V2Ray need a working DNS to work since they connect to proxy servers by links or sockets instead of tunnels, so they have to use ISP DNS and to be excluded from Simple DNSCrypt.