Don't exclude the sender from receiving the message

Another suggestion for improvement:

Currently the sender is excluded of receiving the message, even if s/he is member of one of the recipient groups. This would be okay if the module would offer an option to receive a copy of the message, just like the normal Contact form does.
Suggestion: either introduce that copy-self option too, or don't remove the sender from the recipient list if s/he would normally be included.
Perhaps even both should be done:
- users would normally expect to receive an email they send to a mailinglist of which they are a member themselves;
- but if they are not a member of the recipients, they still might want a copy.