From Mike Weiblen, added missing export to fix osgTerrain wrapper linking under VS
From Mike Weiblen, added missing export to fix osgTerrain wrapper linking under VS


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