From Alberto Luaces, fixed typo of valid() in warning message
From Alberto Luaces, fixed typo of valid() in warning message


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