Add signoff variable to profile settings.

Signed-off-by: John Snow <john.n.snow@gmail.com>
Add inspect-emails to profile settings.

Signed-off-by: John Snow <john.n.snow@gmail.com>
Always number series with a cover letter

If a cover letter is desired to separate metadata about the commit
from the commit message itself and a user decides to enforce a cover
letter for a single patch, make sure to number the "series" so it is
clear as to what has happened.

Signed-off-by: John Snow <john.n.snow@gmail.com>