Roster options give useful errors if you forget to select users, closes #290
Closes #283, Baptism says Yes if empty
Added Today's Payment and Remaining to Billing tab, closes #284
Added bit.ly link generation to Involvement edit page
Changed the `payment_options`.`total` display name to 'price per person', closes #319
Changed email From field to system email for DMARC compliance
Merge branch 'dev'