Don't parse message body for HEAD responses

   The HEAD method is identical to GET except that the server MUST NOT
   send a message body in the response (i.e., the response terminates at
   the end of the header section).  The server SHOULD send the same
   header fields in response to a HEAD request as it would have sent if
   the request had been a GET, except that the payload header fields
   (Section 3.3) MAY be omitted.

http://tools.ietf.org/html/rfc7231#section-4.3.2
Merge pull request #95 from kxepal/fix-head-request

Don't parse message body for HEAD responses