Merge pull request #177 from jianyan74/master

修改回调签名错误

Merge pull request #172 from hogus2037/master

fixed alipay notify sign validate error

Merge pull request #168 from maxsky/master

Add certificate mode support and test code adjusted.

Merge pull request #162 from maxsky/master

Add complete refund notify and adjust composer.json file.

support `app_auth_token`

support `sys_service_provider_id`

'v3.0.3'

php-doc: use class with namespace

'v3.0-beta.1'