Added handling of null dynamic_cast
Added handling of null dynamic_cast

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