adding speakers as csv string to email template context
Sending email to all speakers per proposal
Adding eg for speakers in email notification template
remove adding to_address, as the primary speaker is already a member of self.proposal.speakers()
Merge branch 'develop' into feature/77-co-speakers-email-notifications
Merge pull request #182 from caktus/feature/77-co-speakers-email-notifications

Feature/77 co speakers email notifications