Fix appveyor config

fix(edns): modify `SourceNetmask` for IPv6 (#260)

Google public dns required ipv6 edns `SourceNetmask` to be no more than 56.

Fix nil pointer dereference for empty edns conifg

Format code; Fix default config

Add dns over http server feature

fix hosts (#240)

When hosts exist but query type do not match, an empty result should be returned.

Add pprof for debug

add https protocol introduction and public resolvers reference (#218)

Using url.Parse to improve address parsing

Support build android and ios executables (#212)

Mobile build with test

Change to ubuntu + mac

Fix build.py

Fix android build

Cleanup the appveyor.yml