Added check to init to prevent crash when no camera manipulator is supplied.
Added check to init to prevent crash when no camera manipulator is supplied.


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