Clean a string so it can be used in the URL.
Can be used to create slug URLS for custom sites or WordPress
function clean($string)
{
$string = str_replace(' ', '-', $string); // Replaces all spaces with hyphens.
$string = preg_replace('/[^A-Za-z0-9\-]/', '', $string); // Removes special chars.
$string = strtolower($string);
// Check there is no double/triple
$string = preg_replace('/-+/', '-', $string);
$string = str_replace('---', '-', $string);
$string = str_replace('--', '-', $string);
$string = rtrim($string, '-');
$string = ltrim($string, '-');
return $string;
}