Remove tcp_nodelay directive

The reasoning here - https://github.com/h5bp/server-configs-nginx/issues/28 - seems to make sense. When we set `tcp_nodelay` to off, we tell Nginx to use Nagle's algorithm to figure out how packets should be buffered with a possible 500ms latency if it can't figure things out in time. This 500ms latency is something that even Nagle says (http://developers.slashdot.org/comments.pl?sid=174457&threshold=1&commentsort=0&mode=thread&cid=14515105) should stay in the 1980s.

Suggesting we remove this directive and leave it to Nginx's default `on` to *not* use Nagle's algorithm.
Merge pull request #238 from 10up/nginx-tcpnodelay

Remove tcp_nodelay directive