BUG: setting a kendo ToolBar item.hidden with type of separator does not work. The separator is still displayed. For example:
```
$("#mytoolbar").kendoToolBar({
    items: [
        {
            type: "button",
            text: "button 1",
            hidden: true
        },
        {
            type: "spearator",
            hidden: true
        }
    ]
});
```

In this case, the button is hidden but the separator is not.