Feature: generate QR code

[Chilledheart]

It should be handy to share configuration to mobile application.

Protocol

You can encode your server configuration to a QR Code.

Put your configuration together like this:

 method:password@hostname:port

Transform it into base64:

 bWV0aG9kOnBhc3N3b3JkQGhvc3RuYW1lOnBvcnQ=

Prepend with ss://

 ss://bWV0aG9kOnBhc3N3b3JkQGhvc3RuYW1lOnBvcnQ=

Generate a QR Code from the url above.

Reference: https://github.com/shadowsocks/shadowsocks/wiki/Generate-QR-Code-for-Android-or-iOS-Clients