RFC23, RFC24, RFC26 now use variable-length command names that end in null octet (valid C strings) instead of fixed-length space padded strings.
- designed for TCP clients and servers - added HTTP client / server example in tests/test_stream.cpp - same as ZMQ_ROUTER + ZMQ_ROUTER_RAW + ZMQ_ROUTER_MANDATORY - includes b893ce set ZMQ_IDENTITY on outgoing connect - deprecates ZMQ_ROUTER_RAW