fix readme.md

Merge pull request aliyun#139 from aliyun/dhc/opti

optimize

Release : 2.9.0

Merge pull request aliyun#136 from aliyun/releaseInfo

release 2.8.5 info

release 2.8.4

Log : release 2.8.3

Log : release 2.8.2

Log:release 2.8.1

release: 2.8.0

1.add GetObjectAcl，DeleteMultiObjects，ListBuckets, ImagePersist function

Merge branch 'master' of https://github.com/aliyun/aliyun-oss-android…

…-sdk