Bobby McFerrinThe show opened with a couple dozen or so sprightly young women taking the stage, dressed in traditional eastern European folk garb. Their conductor, also in costume, raised his hands, signaled the opening downbeat, and out came the sound of serenity. Their voices blended into a rich harmony that recalled the music of cloisters and other forms of early European classical music. The ensemble was Jitro, a celebrated girls choir hailing from the Czech…