Add Autoscaling NotificationConfiguration (#275)
Add Autoscaling NotificationConfiguration (#275)

Refer to AWS docs at http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-as-group.html#cfn-as-group-notificationconfigurations
elmobp/cfndsl,jonjitsu/cfndsl,kornypoet/cfndsl,stevenjack/cfndsl,kornypoet/cfndsl,stevenjack/cfndsl,elmobp/cfndsl