Integrate with email obsfucation modules

Hi there

I added functionality to avoid spam to printed email-adresses for the current 5.1 dev release.
The code is LGPL and borrowed from http://smarty.php.net . It implements a javascript encryption as mentioned here: http://smarty.php.net/manual/en/language.function.mailto.php

Edit guestbook.module around line 618 and replace the if clause with this code

  if (in_array('email', $display) && !empty($entry['anonemail'])) {
    // javascript encoding of emailadress
    
	$string = 'document.write(\'<a href="mailto:'.check_url($entry['anonemail']).'">'.t('E-mail').'</a>\');';
	$js_encode = '';
	for ($x=0; $x < strlen($string); $x++) {
	   $js_encode .= '%' . bin2hex($string[$x]);
	}
    $output .= '&nbsp;|&nbsp;<script type="text/javascript">eval(unescape(\''.$js_encode.'\'))</script>';
  }

Please review.
I'd be happy if you would add it to SVN.

Greets.