允许在桥接的view.xib中指定file‘s owner

1、桥接的`UIView`子类需要实现`+ (Class)xx_ownerClass`方法：
```
+ (Class)xx_ownerClass
{
    return [IHMRTInfoViewOwner class];
}
```

2、在`IHMRTInfoViewOwner`类中添加`IBOutlet`属性：
```
@interface IHMRTInfoViewOwner : NSObject

@property (weak, nonatomic) IBOutlet UILabel *numLabel;
@property (weak, nonatomic) IBOutlet UILabel *titleLabel;

@end
```
3、在xib文件中指定`file owner`的`class`为`IHMRTInfoViewOwner`，就可以连接属性了。

属性连接成功后，在vc中可以通过view.owner来访问view的属性。
```
owner = (IHMRTInfoViewOwner *)self.infoView.owner;
[owner setNum:@"0"];
[owner setTitle:@"title"];
```