Merge branch 'master' into mavlink_stack

src/modules/mavlink/mavlink_stream.h

@@ -55,9 +55,13 @@ public:
 	MavlinkStream *next;
 
 	MavlinkStream();
-	~MavlinkStream();
+	virtual ~MavlinkStream();
 	void set_interval(const unsigned int interval);
 	void set_channel(mavlink_channel_t channel);
+
+	/**
+	 * @return 0 if updated / sent, -1 if unchanged
+	 */
 	int update(const hrt_abstime t);
 	static MavlinkStream *new_instance();
 	static const char *get_name_static();