Added material variations examples to list.

examples/index.html

@@ -313,6 +313,10 @@
 				"webgl_materials_texture_manualmipmap",
 				"webgl_materials_texture_pvrtc",
 				"webgl_materials_texture_tga",
+				"webgl_materials_variations_basic",
+				"webgl_materials_variations_lambert",
+				"webgl_materials_variations_phong",
+				"webgl_materials_variations_physical",
 				"webgl_materials_video",
 				"webgl_materials_wireframe",
 				"webgl_mirror",