Menu Item Class

I solved it by editing the plugin like so:

stream-status-widget.php from line 120

$var_status_class = $is_on ? 'lsb-on' : 'lsb-off';
$var_url = $menu_item->url;
$var_title = apply_filters( 'lsb_stream_status_widget_text', $menu_item->title );
$var_status_indicator = $is_on ? $stream->watching_now : 'Offline';
$var_item_classes = implode(" ",$menu_item->classes);  // added

$item = '';
if ($show_image == true) {
	$item = $templates->printt( $lsb_status_widget_item_with_image_format,
		array(
			'%%status_class%%'     => $var_status_class,
			'%%url%%'              => $var_url,
			'%%title%%'            => $var_title,
			'%%status_indicator%%' => $var_status_indicator,
			'%%image_src%%'        => $var_image_src,
			'%%item_classes%%'	   => $var_item_classes  // added
		)
	);
} else {
	$item = $templates->printt( $lsb_status_widget_item_format,
		array(
			'%%status_class%%'     => $var_status_class,
			'%%url%%'              => $var_url,
			'%%title%%'            => $var_title,
			'%%status_indicator%%' => $var_status_indicator,
			'%%item_classes%%'	   => $var_item_classes  // added
		)
	);
}

and class-templates.php lines 18 and 29

<li class="lsb-status-widget-list-item %%status_class%% %%item_classes%%">