Julianne Boyd, Barrington Stage Company artistic director, says when BSC started developing “A Crossing'', about the risks of Mexican immigrants entering the US, six years ago she feared that by the time it was stage-ready it might no longer be relevant. Sadly, that concern is pathetically ironic but BSC has produced not only one of the finest musicals in its impressive history of developing new work, but also a moving, inspirational tale of tragedy and hope that is more