Refactoring

common/cpp/include/common/error.h

common/cpp/include/common/networking.h

common/cpp/include/system_wrappers/io.h

common/cpp/include/system_wrappers/system_io.h

common/cpp/include/unittests/MockIO.h

common/cpp/src/system_io/system_io.cpp

common/cpp/src/system_io/system_io_linux.cpp

common/cpp/src/system_io/system_io_windows.cpp

producer/api/src/producer_impl.cpp

producer/api/unittests/test_producer_impl.cpp

receiver/src/network_producer_peer.cpp

receiver/src/network_producer_peer_handlers.cpp

tests/system_io/ip_tcp_network/ip_tcp_network.cpp