LGSemiModalNavController视图控件动态量显示

LGSemiModalNavController 是一个 UINavigationController 的子类，使用 UIViewControllerAnimatedTransitioning 协议，在视图控件显示自身的动态量。

示例：

//This is an example.
    LGViewController *lgVC = [[LGViewController alloc]initWithFormat:LGViewControllerFormatGoBack];
    //This is the nav controller
    LGSemiModalNavViewController *semiModal = [[LGSemiModalNavViewController alloc]initWithRootViewController:lgVC];
    //Make sure to set a height on the view controller here.
    semiModal.view.frame = CGRectMake(0, 0, self.view.frame.size.width, 400);
    //Selected customization properties, see more in the header of the LGSemiModalNavViewController
    semiModal.backgroundShadeColor = [UIColor blackColor];
    semiModal.animationSpeed = 0.35f;
    semiModal.tapDismissEnabled = YES;
    semiModal.backgroundShadeAlpha = 0.4;
    semiModal.scaleTransform = CGAffineTransformMakeScale(.94, .94);
    [self presentViewController:semiModal animated:YES completion:nil];