Slightly reworked glTF samples

Parent matrices are now applied (where available)
Now more in line with the base code glTF loader
Refs #964

data/shaders/glsl/gltfloading/mesh.frag

@@ -17,7 +17,7 @@ void main()
 	vec3 N = normalize(inNormal);
 	vec3 L = normalize(inLightVec);
 	vec3 V = normalize(inViewVec);
-	vec3 R = reflect(-L, N);
+	vec3 R = reflect(L, N);
 	vec3 diffuse = max(dot(N, L), 0.15) * inColor;
 	vec3 specular = pow(max(dot(R, V), 0.0), 16.0) * vec3(0.75);
 	outFragColor = vec4(diffuse * color.rgb + specular, 1.0);