A aliyun oss adapter for flysystem.

Note: setVisibility总是返回false. SDK没有提供删除目录，所以deleteDir也总是返回false.

SDK 可直接从阿里云下载，也可使用本人的composer包，对SDK未作任何改动。

demo code:

<?php

use League\Flysystem\Filesystem;
use League\Flysystem\AliyunOSS\AliyunOSSAdapter;

$OSSClient = new \ALIOSS($accessKey, $accessSecret, $endPoint);

$adapter = new AliyunOSSAdapter($OSSClient, 'files-bucket');
$flysystem = new Filesystem($adapter);

$flysystem->write('test.txt', 'this is test file content.');

TODO：

完善单元测试