Disable Nagle's algorithm in server and client

This commit disables the Nagle's algorithm to reduce delay when
exchanging values between R and Ruby.

In a particular program I'm working on, I noticed that the exchange
of values between R and Ruby was more time consuming than 
the complex calculation itself.

An example of the Naggle impact here:
http://stackoverflow.com/questions/16776975/ruby-socket-performance-characteristics

Ref.
http://svitsrv25.epfl.ch/R-doc/library/gtools/html/setTCPNoDelay.html