* Problem: missing test for status code 300, inadequate assertion for status code 500
Solution: add test, change assertion (currently test fails)
* Problem: gcc compiler error deprecated conversion from string constant
Solution: declare variable as const
* Problem: in case of ZAP handler returning a status code other than 200, no appropriate event is emitted
Solution: immediately emit event after receiving reply from ZAP handler
* Problem: endpoint address is not included in zap-reply monitor event
Solution: added functions to retrieve endpoint address in zmq::i_engine and zmq::session_base_t
removed unused code block in zmq::stream_engine_t::next_handshake_command
* Problem: wrong formatting
Solution: fix formatting
* Problem: test fails because of EPIPE
Solution: add EPIPE/ECONNRESET/ECONNAGAIN handling for more test cases
