Added file extension guard to .obj reader plugin.
Added file extension guard to .obj reader plugin.


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