Whipe out all 'from' of info@sfiab.ca (the old default, we dont want others using it!)
When sending emails, if 'from' is empty, use the $config['fairmanageremail']
Add a warning on the communication page if the fair manager email has not been set
Set the default 'from' for new emails to be the fair manager email
NOTE/FIXME: i added the hooks for the two new emails to be sent, but still
need to fill in the substitution values as well as the "to" - no time now,
will do that tomorrow
