title: Reading and altering the to/cc/bcc fields programmatically in a Mail.app plugin
body: <p>Has anyone ever successfully figured out the method to alter the to, cc and bcc fields of an outgoing message in a Mail.app plugin? I've been looking through the header files trying to figure out exactly what I need to do to get the list of recipients of the message, and have the ability to alter them (specifically, to remove some recipients and switch the remaining recipients to be bcc'ed).  </p>
  
  <p>Note: I know where I would need to look to find out how to do this, but I've spent some time on that and there are a lot of different classes that do this and the amount of guesswork needed is nontrivial.  I'm merely hoping someone has gone through this already in the past and can save me from the duplicate effort.</p>