Statically-typed functions for simple gesture recognisers

StaticGestureRecognisers.swift

protocol Tappable : AnyObject {
    func handleTap(gr : UITapGestureRecognizer)
}

extension UITapGestureRecognizer {
    convenience init(target : Tappable) {
        self.init(target: target, action: "handleTap:")
    }
}

protocol LongPressable : AnyObject {
    func handleLongPress(gr : UILongPressGestureRecognizer)
}

extension UILongPressGestureRecognizer {
    convenience init(target : LongPressable) {
        self.init(target: target, action: "handleLongPress:")
    }
}

protocol Pannable : AnyObject {
    func handlePan(gr : UIPanGestureRecognizer)
}

extension UIPanPressGestureRecognizer {
    convenience init(target : Pannable) {
        self.init(target: target, action: "handlePan:")
    }
}