adding .gitignore
adding fdstream.hpp

taken from http://www.josuttis.com/cppcode/fdstream.hpp.  This allows us
to create std::ostream and std::istream wrappers around file
descriptors.  We can thus call pipe() to set up two-way communication
between NCM and Stockfish with minimal changes to the Stockfish source
code.
minimal changes to intercept Stockfish uci