Feature Request: Mode Support

[OR13]

Per our lack conversation it would be awesome to support QR Encoding Mode selection.

[JaceHensley]

I'd love to support this, it'll probably involve forking qr.js or copying the files into this lib with the license and modifing it. Because that library only supports bit encoding. And I haven't seen another library that only has the core qr stuff without being attached to a UI implementation

[JaceHensley]

@OR13 I've got a PR up here #14 to support the other modes, still working on adding tests tho