Made improvements to osg::AnimationPath, added

osg::PositionAttitudeTransform::AnimationPathCallback which us an app callback
which uses an AnimationPath to specify the new positions of the transform.

Added AnimationPath code to osglight to animate the positional light.

Added CullVisitor::setCullingMode() code into SceneView so that SceneView's
CullingMode is now properly passed onto CullVisitor.  Note, this work
had been done before, but must has been lost in a merge. Umm...

src/osgUtil/SceneView.cpp

@@ -366,6 +366,7 @@ void SceneView::cullStage(osg::Matrix* projection,osg::Matrix* modelview,osgUtil
          cullVisitor->setTraversalNumber(_frameStamp->getFrameNumber());
     }
 
+    cullVisitor->setCullingMode(_cullingMode);
     cullVisitor->setComputeNearFarMode(_computeNearFar);
     cullVisitor->setLODBias(_LODBias);
     cullVisitor->setSmallFeatureCullingPixelSize(_smallFeatureCullingPixelSize);