Added osg::FrameStamp::set/getSimulationTime().

Added setting of osg_SimulationTime and osg_DeltaSimulationTime to the uniforms set by SceneView

Added frame(double simulationTime) and advance(double simulationTime) parameters to
osgViewer::SimpleViewer, Vewer and CompositeViewer.

Updated various examples and Nodes to use SimulationTime where appropriate.

src/osgPlugins/Inventor/PendulumCallback.cpp

@@ -34,7 +34,7 @@ void PendulumCallback::operator() (osg::Node* node, osg::NodeVisitor* nv)
     // can be shared between multiple parents.
     if (nv->getTraversalNumber()!=_previousTraversalNumber)
     {
-        double currentTime = fs->getReferenceTime();
+        double currentTime = fs->getSimulationTime();
         _angle += (currentTime - _previousTime) * 2 * osg::PI * _frequency;
         
         double frac = 0.5 + 0.5 * sin(_angle);