Fails to decode content encoding when “content-transfer-encoding” header does not contain value in all lower case

http://code.google.com/p/php-mime-mail-parser/issues/detail?id=15

PHP Notice: Undefined index: content-transfer-encoding in /path/to/php-mime-mail-parser/MimeMailParser.class.php on line 193

http://code.google.com/p/php-mime-mail-parser/issues/detail?id=16