Use IB to setup border and shadow layer color

CALayer+InterfaceBuilder.swift

import UIKit
import QuartzCore

extension CALayer {
    
    @objc var borderUIColor: UIColor {
        set {
            self.borderColor = newValue.cgColor
        }
        
        get {
            return UIColor(cgColor: self.borderColor!)
        }
    }
    
    @objc var shadowUIColor: UIColor {
        set {
            self.shadowColor = newValue.cgColor
        }
        
        get {
            return UIColor(cgColor: self.shadowColor!)
        }
    }
    
}