     /**
     Adds a tap gesture recognizer to the receiver's view.
     
+        let f = C4Rect(0,0,100,100)
+        let v = C4View(frame: f)
+        v.addTapGestureRecognizer { location, state in
+            println("tapped")
+        }
+
     :param: action A block of code to be executed when the receiver recognizes a tap gesture.
     :returns: A UITapGestureRecognizer that can be customized.
     */

    /**
    Initializes a new C4View with the specifed frame.
    
    :param: frame A C4Rect, which describes the view’s location and size in its superview’s coordinate system.
    */
    convenience public init(frame: C4Rect) {

            v.view.removeFromSuperview()
        }
    }

    /**
    Moves the specified subview so that it appears behind its siblings.

    When working with C4, use this method because it handles both UIView and C4View.

    :param: view The subview to move to the back.
    */
    public func sendToBack<T>(subview:T) {
        if let v = subview as? UIView {
            self.sendSubviewToBack(v)
