Barbican Pit, LondonA programme of MacMillan's early works by his former ballerina Viviana Durante is brimming with tricksIn the early 1950s, Kenneth MacMillan saw little in the world of ballet that was a true reflection of himself. Scottish and working-class, he struggled to find his place within the opera house establishment; part of a generation of angry young men, he struggled to find value in a repertory that se…