message: layout NVBarButton to match frame of button on iOS
diff: return self;
  }
  +- (void)layoutSubviews
  +{
  + [super layoutSubviews];
  + UIView *buttonView = ((UIView *) [self.button valueForKey:@"view"]);
  + UIView *rightBarView = buttonView.superview;
  + UIView *labelView = buttonView.subviews.count > 0 ? buttonView.subviews[0] : buttonView;
  + CGRect labelFrameInBar = [buttonView convertRect:labelView.frame toView:rightBarView];
  + self.frame = [rightBarView convertRect:labelFrameInBar toView:nil];
  +}
  +
  - (void)setTitle:(NSString *)title
  {
  self.button.title = title;
  