Email History Records - Replace Tokens Before Saving to the DB

Currently, if you place tokens in the body of an email message and send it using the built-in "Send Email to Contact(s)" task - the tokens are parsed/replaced on the sent mail, BUT the message is stored in civicrm_email_history with the raw tokens. Given that we are storing a separate email_history for each contact/recipient - and the admin can view the sent msg via Activity History "details" - we should store the msg w/ the tokens replaced with contact data values.