First example; simple client/server sending simple messages

Both C and C++; following:
http://zguide.zeromq.org/page:all

Signed-off-by: Rodrigo Oliveira <rodrigo@simb.com.br>
Adding cmake as build system for C and C++ examples

Signed-off-by: Rodrigo Goncalves de Oliveira <rodrigo@thecoreme.org>