Merge branch 'master' into develop
Add chan for get access token.
Fix the first to get access token
Post message and retry
Add download media file.
Add example for download media file
Merge pull request #2 from wizjin/develop

Add download media file.
Add multipart post
Add filename for post media file
Fix parse upload response
Add upload into readme
close issue #3
Merge pull request #4 from wizjin/develop

Release v0.3
Merge pull request #1 from wizjin/master

合并原作者更新