Change to inherit from UIControl

This allows the developer to add targets and selectors to the view which means you can use a customview right and left nav with this class.

I have tested this change on my local project

Here is what it allows me to create

 STIconView *logout = [factory iconViewForIconNamed:@"logout" withSide:32.0f];
    [logout addTarget:self action:@selector(logout:) forControlEvents:UIControlEventTouchUpInside];
    UIBarButtonItem * rightBarButtonItem = [[UIBarButtonItem alloc]initWithCustomView:logout];

    self.navigationItem.rightBarButtonItem = rightBarButtonItem;

A custom view bar button item doesn't come with a target or selector. The view being passed to it is supposed to handle the target and selector.