From Tanguy Fautre, This fixes the OSG crashes reported by http://lists.openscenegraph.org/pipermail/osg-users-openscenegraph.org/2009-February/023499.html

It's a one line change against OSG 2.8.0 (see line 196). I've already tested the change, and confirmed it\u2019s fixing the crashes described above."

merged from svn trunk using:

svn merge -r 9797:9798  http://www.openscenegraph.org/svn/osg/OpenSceneGraph/trunk/src/osg/State.cpp

src/osg/State.cpp

@@ -193,6 +193,7 @@ void State::reset()
         ++apitr)
     {
         (*apitr)->resetAppliedUniforms();
+        (*apitr)->removeObserver(this);
     }
     
     _appliedProgramObjectSet.clear();