Fixed effective leak in Program::PerContextProgram caused by previously osg::State keeping a set of std::ref_ptr<Program::PerContextProgram> without ever pruning this list.

The fix was to convert the osg::State to use C pointers for the set of applied PerContexProgram objects, and use the osg::Oberver mechanism to avoid dangling pointers for being maintained in osg::State.

src/osgWrappers/osg/State.cpp

@@ -43,6 +43,7 @@ END_REFLECTOR
 BEGIN_OBJECT_REFLECTOR(osg::State)
 	I_DeclaringFile("osg/State");
 	I_BaseType(osg::Referenced);
+	I_BaseType(osg::Observer);
 	I_Constructor0(____State,
 	               "",
 	               "");
@@ -716,6 +717,11 @@ BEGIN_OBJECT_REFLECTOR(osg::State)
 	          __void__initializeExtensionProcs,
 	          "Initialize extension used by osg:State. ",
 	          "");
+	I_Method1(void, objectDeleted, IN, void *, object,
+	          Properties::VIRTUAL,
+	          __void__objectDeleted__void_P1,
+	          "",
+	          "");