Only auto-complete gps information when empty.

Previously gps information was always overwritten, unless the user had
modified it in the current editing session. This causes problem with
some use cases, like when coordinates are provided before the location
name by the companion app.

Now gps information is only overwritten when it is:
  - Empty
  - Auto-completed in the current editing session. (When the user hits
    accept it is considered hand-edited.)

Signed-off-by: Michael Andreen <harv@ruin.nu>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-ui/maintab.h

@@ -99,6 +99,7 @@ private:
 	void resetPallete();
 	void saveTags();
 	QString printGPSCoords(int lat, int lon);
+	void updateGpsCoordinates(const struct dive *dive);
 };
 
 #endif