Added proper handling of unhandled file return type.
Added proper handling of unhandled file return type.


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