Empty custom header leads to Header code in email body

This bug eventually applies to higher versions, too, so please check

There is a bug in the function CreateHeader().

Around line 1045, additional headers are applied to the email, if there are any.
I used this module in combination with modr8, and somehow it happend, that there was an empty element in the additional header array passed to user_mail.

This leads to a portion of code in the email message body visible to the recipient, e.g.:

:  <-- This is the error!
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain; charset="utf-8"

So there should be some kind of checking for empty elements, like

        // Add custom headers
        for($index = 0; $index < count($this->CustomHeader); $index++)
        {
                   $result .= ($this->CustomHeader[$index][0]) ? $this->HeaderLine(trim($this->CustomHeader[$index][0]), 
                       $this->EncodeHeader(trim($this->CustomHeader[$index][1]))) : '';
        	}
        }