Added desciptions to all the demos.

examples/osgstereoimage/osgstereoimage.cpp

@@ -395,6 +395,7 @@ int main( int argc, char **argv )
     osg::ArgumentParser arguments(&argc,argv);
     
     // set up the usage document, in case we need to print out how to use this program.
+    arguments.getApplicationUsage()->setDescription(arguments.getApplicationName()+" is the example which demonstrates use node masks to create stereo images.");
     arguments.getApplicationUsage()->setCommandLineUsage(arguments.getApplicationName()+" [options] image_file_left_eye image_file_right_eye");
     arguments.getApplicationUsage()->addCommandLineOption("-d <float>","Time delay in sceonds between the display of successive image pairs when in auto advance mode.");
     arguments.getApplicationUsage()->addCommandLineOption("-a","Enter auto advance of image pairs on start up.");