make it possible to override the help label blocks

For example i wan't change the `help_label_tooltip_title` block.

```jinja
<p class="help-inline">
        <a href="#" id="{{ id }}" title="{{ help_label_tooltip_title|trans({}, translation_domain) }}" data-toggle="tooltip" data-placement="{{ help_label_tooltip_placement }}"><i class="icon-info-sign"></i></a>
    </p>
```

and add a global js 
``` js
$('.help-inline').tooltip({
    selector: "a[data-toggle=tooltip]"
});
```