Added support for CURVE security examples
Added support for CURVE security examples

Added libsodium reference
chenwenbin928/zmqpp,pin3da/zmqpp,kernelim/zmqpp,zeromq/zmqpp,datasift/zmqpp,zeromq/zmqpp,benjamg/zmqpp,datasift/zmqpp,xaqq/zmqpp,benjamg/zmqpp,xaqq/zmqpp,pin3da/zmqpp,chenwenbin928/zmqpp,sunkin351/zmqpp,sunkin351/zmqpp,kernelim/zmqpp