Prevent trying to open() menus without any items

[Lynesth]

Or at least handle it correctly. It crashes when trying to move the selection.

[AydinHassan]

@Lynesth is this still the case? I can't reproduce this on master

[Lynesth]

Yep I confirm this still is the case on master.

You can reproduce it like this:

<?php

use PhpSchool\CliMenu\CliMenu;
use PhpSchool\CliMenu\CliMenuBuilder;

require_once(__DIR__ . '/../vendor/autoload.php');

$itemCallable = function (CliMenu $menu) {
    echo $menu->getSelectedItem()->getText();
};

$menu = (new CliMenuBuilder)
    ->disableDefaultItems()
    ->build();

$menu->open();