Renamed osg::Primitive to osg::PrimitiveSet which better reflect what it

encapsulates.

Added new osg::IndexGeometry implemention, *not* complete yet.

Changed the rest of the OSG to handle the renaming og Primitive to PrimitiveSet.

src/osg/Geometry.cpp

@@ -28,7 +28,7 @@ Geometry::Geometry(const Geometry& geometry,const CopyOp& copyop):
         pitr!=geometry._primitives.end();
         ++pitr)
     {
-        Primitive* primitive = copyop(pitr->get());
+        PrimitiveSet* primitive = copyop(pitr->get());
         if (primitive) _primitives.push_back(primitive);
     }