presentModalViewController的动画

转来的，没验证，，，以后有需要的时候在看

   self.myPushNav = [[MyPushNavViewController alloc] init];
    CATransition *animation = [CATransition animation];
    animation.duration = 5.0;
    animation.timingFunction = UIViewAnimationCurveEaseInOut;
    animation.type = @"pageCurl";
    animation.subtype = kCATransitionFromLeft;
    [self.view.window.layer addAnimation:animation forKey:nil];
    [self presentModalViewController:myPushNav animated:NO];