Adjust copyrights years

<?php
/**
 * SeekQuarry/Yioop --
 * Open Source Pure PHP Search Engine, Crawler, and Indexer
 *
 * Copyright (C) 2009 - 2020  Chris Pollett chris@pollett.org
 *
 * LICENSE:
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 * END LICENSE
 *
 * @author Chris Pollett chris@pollett.org
 * @license https://www.gnu.org/licenses/ GPL3
 * @link https://www.seekquarry.com/
 * @copyright 2009 - 2020
 * @filesource
 */
namespace seekquarry\yioop\views\helpers;

use seekquarry\yioop\configs as C;
use seekquarry\yioop\library\CrawlConstants;

/**
 * Helper used to draw thumbnails strips for images
 *
 * @author Chris Pollett
 */
class ImagesHelper extends Helper implements CrawlConstants
{
    /**
     * Takes page summaries for image pages and the current query
     * and draw a thumbnail strip so that clicking on an image goes to
     * the cache of that image.
     *
     * @param array $image_pages page data and thumbnails for images
     * @param string $query the current search query
     * @param string $subsearch name of subsearch page this image group on
     * @param bool $image_subsearch whether the image subsearch is
     *  enabled on this Yioop instance
     */
    public function render($image_pages, $query, $subsearch,
        $image_subsearch = true)
    {
        if ($subsearch != 'images' && !stristr($query, "media%3Aimage")) {
            if ($image_subsearch) {
                $query .= '&s=images';
            } else {
                if (!stristr($query, "media%3Aimage")) {
                    $query .= '%20media%3Aimage';
                }
            }
            ?>
            <h2><a href="<?= $query ?>"
                ><?=tl('images_helper_view_image_results') ?></a></h2>
                <?php
        }
        ?><div class="image-list">
        <?php
        $i = 0;
        $break_frequency = 5;
        foreach ($image_pages as $page) {
            if (C\CACHE_LINK && (!isset($page[self::ROBOT_METAS]) ||
                !(in_array("NOARCHIVE", $page[self::ROBOT_METAS]) ||
                  in_array("NONE", $page[self::ROBOT_METAS])))) {
                $link = $query."&amp;a=cache&amp;arg=" .
                    urlencode($page[self::URL]) .
                    "&amp;its=" . $page[self::CRAWL_TIME];
            } else {
                $link = htmlentities($page[self::URL]);
            }
            ?>
            <a href="<?= $link ?>" rel="nofollow"><img src="<?=
                $page[self::THUMB] ?>" alt="<?= $page[self::TITLE] ?>" />
            </a><?php
            $i++;
            if ($i % $break_frequency == 0) {
                e('<br />');
            }
        }
        ?>
        </div>
        <?php
    }
}