RETrimControliOS音频微调控制

RETrimControl 是 iOS音频微调控制，类似 iPhone 语言备忘录应用。

示例代码：

RETrimControl *trimControl = [[RETrimControl alloc] initWithFrame:CGRectMake(10, (self.view.frame.size.height - 28) / 2.0f, 300, 28)];
trimControl.length = 200; // 200 seconds
trimControl.delegate = self;
[self.view addSubview:trimControl];