default components file

I'd like to change the default components file to include a folder copy:

To:
cc:
Fcc: +sent-mail
Subject:
--------

Most mail clients I've dealt with make a copy of sent mail by default, and
it's easier for new users to delete a line than to figure out how to
correctly add one.

I'll change the 'comp' man page too, if everyone agrees.

Thanks.