Add ability to send emails with "Request a Read Receipt" option. It would also be nice if this could be flexible with the following option.

1. Manually indicating "Request a Read Receipt"
2. Having a Boolean field for each email scenario
3. For example, if they are just using one email account for multiple email scenarios, they should be able to select which scenarios "Request a Read Receipt" will default to true.
4. Having a Boolean field for each email account
5. Basically any email sent from BC through an email account that has the Boolean set to true, will send an email with 'Request a Read Receipt'