SafeIsHidden.swift

extension UIView {
    /// Sets `isHidden` but only if the new value is different from the existing one.
    /// Fixes http://stackoverflow.com/questions/33240635/hidden-property-cannot-be-changed-within-an-animation-block
    var safeIsHidden: Bool {
        get {
            return isHidden
        }
        set {
            if newValue != isHidden {
                isHidden = newValue
            }
        }
    }
}