Update payment_reminder_mailer.rb
Locales are a child of spree:
Merge pull request #3 from reinaris/patch-2

Prefix translations with Spree
Merge branch 'master' of github.com:Willianvdv/spree_mitch_buchannon into 2-2-stable
Bumped versions
Merge branch '2-2-stable' of github.com:Willianvdv/spree_mitch_buchannon into 2-2-stable

Conflicts:
	app/mailers/spree/payment_reminder_mailer.rb
Re-added development dependencies
Fixed spec