added tutorial: changing navigation mode
added tutorial: changing navigation mode

OpenWebGlobe/WebViewer,robhawkes/WebViewer,OpenWebGlobe/WebViewer,robhawkes/WebViewer,OpenWebGlobe/WebViewer,Hvitnov/WebViewer,robhawkes/WebViewer,Hvitnov/WebViewer,Hvitnov/WebViewer,OpenWebGlobe/WebViewer,robhawkes/WebViewer,Hvitnov/WebViewer