[nacltoons] Rename core classes in accordance with doc.

nacltoons/bindings/lua_level_layer.h

Index: nacltoons/bindings/lua_level_layer.h
diff --git a/nacltoons/bindings/lua_physics_layer.h b/nacltoons/bindings/lua_level_layer.h
similarity index 64%
rename from nacltoons/bindings/lua_physics_layer.h
rename to nacltoons/bindings/lua_level_layer.h
index 8e8233ce2f8ad478a37c27c7be0e3044afd917c0..c843e694f6fa38d3d241b9dabd20ffcbaaab0bf6 100644
--- a/nacltoons/bindings/lua_physics_layer.h
+++ b/nacltoons/bindings/lua_level_layer.h
@@ -1,5 +1,5 @@
 /*
-** Lua binding: physics_layer
+** Lua binding: level_layer
 ** Generated automatically by tolua++-1.0.93 on Wed Feb 27 11:18:21 2013.
 */
 
@@ -9,4 +9,4 @@ extern "C" {
 }
 
 /* Exported function */
-TOLUA_API int  tolua_physics_layer_open (lua_State* tolua_S);
+TOLUA_API int  tolua_level_layer_open (lua_State* tolua_S);