Added an empty() method
Added an empty() method


openscenegraph/osg,marchelbling/osg,tomasthoresen/osg,openscenegraph/osg,openscenegraph/osg,marchelbling/osg,artoolkit/osg,marchelbling/osg,scrawl/osg,tomasthoresen/osg,artoolkit/osg,tomasthoresen/osg,scrawl/osg,jtorresfabra/osg,artoolkit/osg,jtorresfabra/osg,jtorresfabra/osg,marchelbling/osg,artoolkit/osg,jtorresfabra/osg,scrawl/osg,openscenegraph/osg,tomasthoresen/osg,scrawl/osg