Manually clear dns cache on mavericks
Please check RFC1035, DNS protocol and Understanding the dig command.
If the status is SERVFAIL (Server failure. The name server was unable to process this query due to a problem with the name server) you won't get an ANSWER section.

I don't think the problem is on your side.

In 7 attempts querying several name servers i only got one answer:  

dig @208.67.220.220 codeship.com
; &lt;&lt;&gt;&gt; DiG 9.8.5-P1 &lt;&lt;&gt;&gt; codeship.com
;; global options: +cmd
;; Got answer:
;; -&gt;&gt;HEADER&lt;&lt;- opcode: QUERY, status: NOERROR, id: 36214
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;codeship.com.          IN  A

;; ANSWER SECTION:
codeship.com.       0   IN  A   54.243.124.75
codeship.com.       0   IN  A   54.225.96.71
codeship.com.       0   IN  A   54.221.223.218

;; Query time: 6126 msec
;; SERVER: 208.67.220.220#53(208.67.220.220)
;; WHEN: Tue Dec 02 02:03:36 CET 2014
;; MSG SIZE  rcvd: 78