Enable stricter compile mode and ensure the most relevant bits are initialized. Needs more work to avoid the remaining warnings

src/modules/mavlink/mavlink_main.cpp

@@ -216,6 +216,7 @@ Mavlink::Mavlink() :
 	_device_name(DEFAULT_DEVICE_NAME),
 	_task_should_exit(false),
 	next(nullptr),
+	_instance_id(0),
 	_mavlink_fd(-1),
 	_task_running(false),
 	_hil_enabled(false),
@@ -230,17 +231,24 @@ Mavlink::Mavlink() :
 	_mission_pub(-1),
 	_mission_result_sub(-1),
 	_mode(MAVLINK_MODE_NORMAL),
+	_channel(MAVLINK_COMM_0),
+	_logbuffer{},
 	_total_counter(0),
+	_receive_thread{},
 	_verbose(false),
 	_forwarding_on(false),
 	_passing_on(false),
 	_ftp_on(false),
 	_uart_fd(-1),
+	_baudrate(57600),
+	_datarate(10000),
 	_mavlink_param_queue_index(0),
+	mavlink_link_termination_allowed(false),
 	_subscribe_to_stream(nullptr),
 	_subscribe_to_stream_rate(0.0f),
 	_flow_control_enabled(true),
-	_message_buffer({}),
+	_message_buffer{},
+	_message_buffer_mutex{},
 	_param_initialized(false),
 	_param_system_id(0),
 	_param_component_id(0),