Refactored timeout and send_period for heartbeat into default values dict in Waldo.py. This will allow the user to set the default timeout easily, and it separates application logic from configuration.
Adjusted default heartbeat period to 30 seconds.
Implemented setters for the default heartbeat send period and timeout period. You may now call Waldo.set_default_timeout or Waldo.set_default_heartbeat_period to configure these values before calling tcp_accept or tcp_connect.