Wrap URLs in tweets in a tags.

_applyEntities.php

<?php
private static function _applyEntities(&$feed)
{
    if (null !== $feed) {
        foreach($feed as &$item) {
            if (null !== $item['entities']['urls']) {
                $urls    = array_reverse($item['entities']['urls']);
                $content = &$item['text'];
                foreach ($urls as $url) {
                    $content = substr_replace($content, '</a>', $url['indices'][1], 0);
                    $content = substr_replace($content, '<a href="'.$url['url'].'">', $url['indices'][0], 0);
                }
                unset($content);
            }
        }
        unset($item);
    }
}