Update the README.md
Fix comments for modifier.add_suffix.php
Fix comments for modifier.filesize.php
Fix comments for modifier.mail2link.php
Fix comments for modifier.nl2br.php
Fix comments for modifier.unescape_tag.php
Fix a bug for modifier.unescape_tag.php
Fix comments for modifier.url2link.php

Signed-off-by: Kaoru Ishikura <ishikura@sakura-creative.com>