Yogi Berra said the future ain't what it used to be. We know how he feels. The Broadway arrival of the West End hit "Back to the Future" continues the march of Hollywood brand extensions to the musical stage. The production, based on the 1985 film hit that spun off two sequels, arrives with a flourish: LED lights flashing, sound system blaring and special effects blazing. All that dazzle might satisfy film fans looki…
