3.1.1

• Fix bug where the socket.write callback was not fired. This affected certain
  cases such as res.render.
• Add unit test for parse-http-response code.
• Fix bug where x-expeditious-cache could return miss when it should be a
  hit.
• Fix bug where sever would respond with 304 to requests without if-none-match
  header in their payload. This manifested itself if the first incoming request
  after cache expiry resulted in a 304 and would cause clients that were new, and
  therefore needed a 200 with data, to receive a 304.