Support swift 4.2 and add display callback

[rerlanggas]

I add some changes for support swift 4.2 and also I add display callback, sometime I need to know both value which is "display" and "value", but the current picker dialog only provide the "value" so I did some changes for the callback to showing "display" and "value", and also I add extension UIColor, becuase in your picker dialog not provide the extension it can cause this line error UIColor(hex: 0x333333)