Added setStateSet(0) to destructors to force the problem clean up of attached

StateSets.

src/osg/Drawable.cpp

@@ -299,6 +299,9 @@ Drawable::Drawable(const Drawable& drawable,const CopyOp& copyop):
 
 Drawable::~Drawable()
 {
+    // cleanly detatch any associated stateset (include remove parent links)
+    setStateSet(0);
+
     dirtyDisplayList();
 }
 

src/osg/Node.cpp

@@ -57,6 +57,8 @@ Node::Node(const Node& node,const CopyOp& copyop):
 
 Node::~Node()
 {
+    // cleanly detatch any associated stateset (include remove parent links)
+    setStateSet(0);   
 }
 
 void Node::addParent(osg::Group* node)