Made the calls to the drawing of the pre rendering stages exclit, using

a seperate method in RenderStage and associated calls in sceneView.cpp.
This fixes problems when doing stereo and prerender at the same time.

include/osgUtil/RenderStage

@@ -108,6 +108,8 @@ class OSGUTIL_EXPORT RenderStage : public RenderBin
             getRenderStageLighting()->addPositionedAttribute(matrix,attr);
         }
         
+        virtual void drawPreRenderStages(osg::State& state,RenderLeaf*& previous);
+        
         virtual void draw(osg::State& state,RenderLeaf*& previous);
 
         void addToDependencyList(RenderStage* rs);

include/osgUtil/SceneView

@@ -281,7 +281,6 @@ class OSGUTIL_EXPORT SceneView : public osg::Referenced
 
         /** Do cull traversal of attached scene graph using Cull NodeVisitor.*/
         virtual void cullStage(osg::Matrix* projection,osg::Matrix* modelview,osgUtil::CullVisitor* cullVisitor, osgUtil::RenderGraph* rendergraph, osgUtil::RenderStage* renderStage);
-        virtual void drawStage(osgUtil::RenderStage* renderStage);
 
         const osg::Matrix computeMVPW() const;