LRGlowingButton

LRGlowingButton 是 UIButton 的之类，可自定义发光颜色，用于替代默认的 showsTouchWhenHighlighted

示例代码：

LRGlowingButton *button = [LRGlowingButton buttonWithType:UIButtonTypeCustom];
button.glowsWhenHighlighted = YES;
button.highlightedGlowColor = [UIColor whiteColor];
[self.view addSubview:button];