ParseN2kPGN129029: Added a documentation note about reference station…

… remaining unchanged in the case the message doesn't contain them.

Also added a newline to the end of N2kMessages.h, as it is required by the language standard.

src/N2kMessages.h

@@ -3157,6 +3157,11 @@ inline void SetN2kGNSS(tN2kMsg &N2kMsg, unsigned char SID, uint16_t DaysSince197
  * This parameter group conveys a comprehensive set of Global Navigation 
  * Satellite System (GNSS) parameters, including position information.
  * 
+ * The parameters passed to ReferenceStationType, ReferenceStationID and AgeOfCorrection
+ * are unchanged when there are no reference stations present in the message.
+ * One way to handle it is to initialize the variables passed to N2kGNSSt_GPS,
+ * N2kInt16NA and N2kDoubleNA respectively, before calling this function.
+ *
  * \param N2kMsg      Reference to a N2kMsg Object, 
  * \param SID         Sequence ID. If your device is e.g. boat speed and
  *                    heading at same time, you can set same SID for
@@ -5680,4 +5685,4 @@ inline bool ParseN2kDirectionData(const tN2kMsg &N2kMsg,tN2kDataMode &DataMode,
 }
 
 
-#endif
+#endif