Squashed 'SinaStorageSDK/' changes from e4dfcd6..123213e

123213e 更新readme

git-subtree-dir: SinaStorageSDK
git-subtree-split: 123213e5956390119d3c203dcdce8754304b0369
Merge commit '1edd5ff2db100eb99aaa45f530d632507a4b8762'