Made the more of the OSG's referenced object desctructors protected to ensure

that they arn't created on the stack inappropriately.

Split the implemention of Matrix up so that it is a simple no referenced counted
class and can be safefly created on the stack.  To support referenced counting a
seperate subclass now exists, this is RefMatrix which inherits from both Matrix and
Object.

src/osg/VertexProgram.cpp

@@ -91,7 +91,7 @@ void VertexProgram::apply(State& state) const
             ++itr)
         {
             ::glMatrixMode((*itr).first);
-            ::glLoadMatrixf((*itr).second->ptr());
+            ::glLoadMatrixf((*itr).second.ptr());
         }
         ::glMatrixMode(GL_MODELVIEW); // restore matrix mode
     }