Mail utilities: switched to the Django mailer
Mail utilities: switched to the Django mailer

This change allows the email backend to be configured in settings, so that a
different backend can be used, e.g., during testing.

codeforboston/cornerwise,codeforboston/cornerwise,cityofsomerville/cornerwise,cityofsomerville/citydash,codeforboston/cornerwise,cityofsomerville/cornerwise,codeforboston/cornerwise,cityofsomerville/cornerwise,cityofsomerville/citydash,cityofsomerville/citydash,cityofsomerville/citydash,cityofsomerville/cornerwise