Improve error msg re https://trello.com/c/yM9WPxzr/107-complaints-about-using-subcriteria-with-populate-on-a-singular-association-when-i-try-to-do-select
Improve error msg re https://trello.com/c/yM9WPxzr/107-complaints-about-using-subcriteria-with-populate-on-a-singular-association-when-i-try-to-do-select

balderdashy/waterline,luislobo/waterline