Update Panel.php

[SamMousa]

Make $tools public to allow directly adding items to the panels menu. Instead of just the headerMenu.

[fps01]

@SamMousa hello!
Thanks for PR.
Could you wrote an usage example for http://gentelella.yiister.ru/site/panel page?

[SamMousa]

<?php
        Panel::begin(
            [
                'header' => 'Panel with extra tool menu items',
                'icon' => 'cog',
                'tools' => [
                    [
                        'label' => 'The first item',
                        'url' => '#',
                    ],
                    [
                        'label' => 'The second item',
                        'url' => '#',
                    ],
                ],
            ]
        )
        ?>