[dns] Add todos and references to README

Author: igorw

README.md

@@ -42,3 +42,14 @@ You can cache results by configuring the resolver to use a `CachedExecutor`:
 
 If the first call returns before the second, only one query will be executed.
 The second result will be served from cache.
+
+## Todo
+
+* Implement message body parsing for types other than A and CNAME: NS, SOA, PTR, MX, TXT, AAAA
+* Implement `authority` and `additional` message parts
+* Respect /etc/hosts
+
+# References
+
+* [RFC1034](http://tools.ietf.org/html/rfc1034) Domain Names - Concepts and Facilities
+* [RFC1035](http://tools.ietf.org/html/rfc1035) Domain Names - Implementation and Specification