Encryptor config.
Add refund_desc, resolve w7corp#802
Fix version,
Apply fixes from StyleCI (w7corp#791) [ci skip] [skip ci]
Bugfix. resolve w7corp#742
Fix PHP compatibility problems. 当 json_decode 空字符串时，PHP7 会返回错误码，PHP5.6 则没有错误发生。
Resolve w7corp#592
Apply fixes from StyleCI (w7corp#780) [ci skip] [skip ci]
Rename API. w7corp#775
Fix comment.