Seattle has struggled to create an identity as a major, American city for as long as I have lived here. Each time, it seemed poised to break out, the provincial mindset, which has long dominated the city’s culture, reasserted itself. For 72 hours last weekend, Seattle’s music and performance finally broke loose, bringning us Heiner Goebbels’ “Songs of Wars I’ve Seen,” a music and theater piece based on Getrude Stein’s writings.