nuget
Merge pull request #46 from icattlecoder/fix/doc

添加nuget安装方式的文档
hotfix
Update RSFClient.cs

98行增加limit参数
Merge pull request #48 from icattlecoder/fix/doc

hotfix
更改参数顺序与原始顺序保持一致
Merge pull request #50 from QingWei-Li/develop

Update RSFClient.cs
Update CHANGELOG.md
Merge pull request #51 from qiniu/develop

Release 6.1.2