IntersectionClasses?

The new osgUtil::IntersectionVisitor at related helper class provide a new general purpose set of ways on computing intersections with scenes, handling different types of intersectors, such as line segments, planes and polytopes, as well as handling paged databases automatically as well as using double precision maths to enable handling of whole earth databases. The original osgUtil::IntersectVisitor and osgUtil::PickVisitor could only handle LineSegment? intersection, and could not handle large scale databases or paged databases.