Added support for reading .osg, .osgb, .osgx, .osgt and .ive models that contain volumes from within the volume tag.
Added support for reading .osg, .osgb, .osgx, .osgt and .ive models that contain volumes from within the volume tag.


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