Merge pull request #42 from deancn/master

fix: resolve dataformat typo and set xml as default dataformat

Merge pull request #41 from deancn/master

feat: add subscribe and unsubscribe event

Merge pull request #27 from bbhj/master

Support Wechat.Set() function

Merge pull request #22 from TomLiu-GitHub/master

New和Set参数保持一致