PR add rake comments and ec2 cleanup task

I didn't realize attached volumes didn't get deleted. Need to add the following before terminating the instance.
http://docs.aws.amazon.com/AWSRubySDK/latest/AWS/EC2/Instance.html#attachments-instance_method
http://docs.aws.amazon.com/AWSRubySDK/latest/AWS/EC2/Attachment.html#delete-instance_method