Fixed normal transformation for the Flash backend

Normals were incorrectly being transformed using the same matrix provided for vertex coordinate transformation. This was changed to use the same method as the WebGL backend. See the following example for a scene that exhibits the problem with the previous implementation.

```xml
<X3D width="400px" height="400px">
  <Scene>
	<Viewpoint position='0 0 10'></Viewpoint>
	<Background skyColor="0.8 0.9 1.0"></Background>
	<transform scale="1 1 0.1">				
		<transform rotation="1 1 0 0.78">
			<Shape DEF='thebox'>
				<Appearance>
					<Material diffuseColor='0.8 0.8 0.8'></Material>
				</Appearance>
				<Box></Box>
			</Shape>
		</transform>
	</transform>
  </Scene>
</X3D>
```