Samuel J Friedman Theatre, New York An adept cast, including Amber Gray, Jessica Hecht and Bill Irwin, bring a sharply funny and timely new play to life By all appearances, the Eureka Day school in Oakland, California, is a progressive, welcoming, warm-hearted place. The shelves of the elementary school's library, as staged at Samuel J Friedman Theatre in a sharp new play by Jonathan Spector, boast a colorful, cacoph…