CGAffineTransform myTransform = CGAffineTransformMakeRotation(
M_PI);
UIBarButtonItem * currentItem = self.navigationItem.leftBarButtonItem;
currentItem.customView.transform = myTransform;
self.navigationItem.leftBarButtonItem.customView.layer.anchorPoint = CGPointMake(0.6, 0.7);
//anchorPoint 회전축. 0.5 0.5가 초기치인듯.
