created branch
add MediaUpload Api
Add MediaGet Api
add HttpHelper
修正HttpHelper.HttpPost 中一处错误
修正post bug
V2.1.1.0
更新被动返回消息
responsetest
Version to V2.2.0.0
1、增加发送客服消息接口
2、增加PublicMessage文件，把一些公共相关信息提取出来
modify test function
delete article.cs
TestMessage -> TextMessage
Merge pull request #2 from JamesYing/master

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