Add comment for modify third-party code.

Source/ThirdParty/toluapp/src/lib/tolua_is.c

@@ -116,6 +116,7 @@ TOLUA_API void tolua_error (lua_State* L, const char* msg, tolua_Error* err)
 }
 
 /* the equivalent of lua_is* for usertable */
+// Modified by Aster Jian for Urho3D.
 static  int lua_isusertable (lua_State* L, int lo, const char* type)
 {
 	int r = 0;

Source/ThirdParty/toluapp/src/lib/tolua_map.c

@@ -394,7 +394,8 @@ TOLUA_API void tolua_usertype (lua_State* L, const char* type)
  char ctype[128] = "const ";
  strncat(ctype,type,120);
 
-	/* create both metatables */
+ /* create both metatables */
+ // Modified by Aster Jian for Urho3D.
  if (tolua_newmetatable(L,ctype) && tolua_newmetatable(L,(char*)type))
 	 mapsuper(L,type,ctype);             /* 'type' is also a 'const type' */
 }