Merge pull request #27 from qiniu/develop

support fileop
Merge pull request #29 from qiniu/develop

fileop: bugfix
Merge pull request #39 from qiniu/develop

Release v2.4.2
Merge pull request #46 from qiniu/develop

Release v2.5.0
Merge pull request #49 from qiniu/develop

Develop
Merge pull request #51 from qiniu/develop

Develop
Merge pull request #54 from qiniu/develop

Release v2.5.1
Merge pull request #61 from qiniu/develop

Release v3.0.0
Merge pull request #64 from qiniu/develop

Releaes v6.0.0
Merge pull request #68 from qiniu/develop

merge develop to master
Merge pull request #72 from qiniu/develop

merge to master
Merge pull request #74 from qiniu/develop

Release 6.0.1
Merge pull request #76 from qiniu/develop

Release 6.0.3
add endUser to json string
change log
Merge pull request #78 from icattlecoder/hotfix/add_enduser

Hotfix/add enduser
Merge pull request #83 from longshanksmo/develop

adjust download domain
Update README.md
Update CHANGELOG.md
merge from master