Add request/response tests
Use gocheck methods to have less test code
Return the SOA record for empty 'noerror' responses so they get cached
Add support for MX records

(ticket #20)
Update to work with latest dns library
Improve service run script, make IP config optional
Write() is now WriteMsg() in the dns library

https://github.com/miekg/dns/commit/267cfaab1164d7a199
dns client now returns rtt from Exchange, update tests to match
Fix quotes in interface parameter
Move configuration for tests to test.example.com
Expand documentation a bit
Fix to work with latest dns library

commit 2a3b818b953114d365e45452cba38ab820150007
Author: Miek Gieben <miek@miek.nl>
Date:   Sun Dec 2 09:29:54 2012 +0100

    Use much more descriptive names for the maps

     Alg_str -> AlgorithmToString
     Rr_str  -> TypeToString

    And for the reverse maps also.
Merge branch 'master' into edns-subnet
set SOA contact
test for contact
Cleanup config_test.go slightly
Make CNAME records optionally use the current zone name

In pgeodns they didn't because the whole data structure
was shared between different origin names if they used
the same .json.
Add serve tests for MX records
Change dns.RR_* to dns.* as per dns library changes
Merge branch 'master' into edns-subnet