A custom segmented control
可以自定义，实现了block，delegate回调
自定义属性有： @property (nonatomic , strong) NSArray *btnTitleArray;
@property (nonatomic , strong) UIColor *btnTitleNormalColor;
@property (nonatomic , strong) UIColor *btnTitleSelectColor;
@property (nonatomic , strong) UIColor *btnBackgroundNormalColor;
@property (nonatomic , strong) UIColor *btnBackgroundSelectColor;
@property (nonatomic , strong) UIFont *titleFont;
