Port agent tg

Changes for implementing break command. Main files added/modified:
 M src/network/tcp_comm_socket.cxx
 M src/network/tcp_comm_socket.h
 M src/port_agent/config/port_agent_config.cxx
 M src/port_agent/config/port_agent_config.h
 M src/port_agent/connection/connection.h
 M src/port_agent/connection/instrument_rsn_connection.h
 M src/port_agent/connection/instrument_rsn_connection.cxx
 M src/port_agent/port_agent.cxx
 M src/port_agent/port_agent.h
 M src/port_agent/publisher/instrument_command_publisher.cxx
 M src/port_agent/test/port_agent_test.cxx