By Michael Rosenberg Nick Baumgartner and Lindsey Jacobellis won gold in mixed team snowboard cross, but allegations of misconduct against their coach made Saturday a difficult day to process. ZHANGJIAKOU, China — Snowboard cross is different from most Winter Olympic events in that athletes actually race alongside each other simultaneously. They don’t perform and then wait to see how the next person does, like in figure skating or Alpine skiing. Saturday morning’s mixed-team event put a different spin on it: Two stories jostled for position, each hellbent on finishing first. Was it the aging s…