[NaCl SDK] rename nacl_io demo.

native_client_sdk/src/examples/demo/nacl_io_demo/example.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 function moduleDidLoad() {
   common.hideModule();
 }
 
 function $(id) {
   return document.getElementById(id);
@@ skipping 329 matching lines @@
       }
 
       delete funcToCallback[funcName];
       callback.apply(null, params);
     }
   } else {
     common.logMessage('Error: Unknow message `' + data +
                       '` received from NaCl module.');
   }
 }