There’s a new resource for spring-break-bound overachievers as well as those who just want to take, say, their French to the next level. International-travel bookstore Idlewild unveiled a Brooklyn offshoot to its Flatiron headquarters last week (249 Warren St., nr. Court St., Cobble Hill; 718-403-9600), focusing exclusively on France, Spain, and Italy. In addition to more than 5,000 foreign-language novels, comics, and children’s books, the next-door storefront offers ten-week language classes ranging from beginner kids’ lessons to Crime Literature and Conversation.