provider invoiced event + refactoring of NotificationMailer + enhancing service_call generator to create the notification view for the mailer
all 111 service call pages spec tests are green
save point for almost completing all billing status events
completed billing state machines + all service_call tests are green
Merge remote-tracking branch 'origin/master'

Conflicts:
	Gemfile.lock
	app/views/affiliates/show.html.erb
subcon settlement working - all service call tests are green
subcon settlement working - all service call tests are green
provider settlement working - all service call tests are green