Release 2.13.0

Release 2.12.0

Release 2.11.0

update comment

Release 2.9.1

Refine Readme

Merge pull request #52 from aliyun/crc

Release 2.8.0

Merge pull request #47 from aliyun/restorebuket

add a new ResumableUploadObject API

Merge pull request #41 from aliyun/restorebuket

 Supports IA/Archive in CreateBucket API and Restore API

Merge pull request #38 from aliyun/develop

four bug fixes