By Jonathan Rosenbaum 1. Two special four-disc sets have become available this quarter to fill in sizable gaps in our grasp of Eastern European cinema during the mid-20th century. First, Polish Cinema Classics from Second Run in the UK, gathering together Andrzej Munk’s Eroica (1957), Jerzy Kawalerowicz’s Night Train (1959), Andrzej Wajda’s Innocent Sorcerors (1960),…