Whitney Tilson has a new short (WING, LL, EXAC)

Whitney Tilson has a new short: Wingstop.
The founder of Kase Capital, who bet against Lumber Liquidators on allegations that the hardwood-flooring retailer sold toxic products, revealed his new short Tuesday at the Robin Hood Conference.
Shares of the chicken-wing chain fell by as much as 3% in regular trading. 
In a slide deck on his Website, Tilson listed five reasons why he was short the stock, or betting that it would fall. 
First, he found the valuation to be "absu