LHLoadingView:它是具有三个块的动画的活动指示器视图的替代方案

LHLoadingView ============ Version 1.1: update to iOS 7&8, fix bugs ============ Version 1.0: It is an alternative to the activity indicator view with three blocks' animation 可以替代activity indicator view的loading 动画，由三个方块组成，循环滚动根据frame，自动适配方块大小