Adds migration to Email Settings for Venue Updates
 [Bugfix] Confirmed / Unconfirmed events over time for conference dashboard
Merge pull request #297 from ChrisBr/bugfix_events_over_time_new

 [Bugfix] Confirmed / Unconfirmed events over time for conference dashboard
Added nil checks for call for papers in event index
Changed first / lastname to name

close #342
close #344
Merge pull request #345 from ChrisBr/bugfix_events_index

Added nil checks for call for papers in event index
Venue update notifications done
Added tests for emails views specs for addition of settings
Merge pull request #318 from gopesht/notify_on_venue_change

Email notification to all participants on venue update
Adds migrations for call for papers updates in email settings
Email notification on cfp dates updates and schedule made public