A chance meeting between an up-and-coming young Canadian choreographer and some Broadway bigwigs appears to have sparked quite an impressive collaboration, and possibly launched a new star into the forefront of the dance galaxy. In the space of only a few months, Aszure Barton has gone from a residency at the Baryshnikov Center in lower Manhattan to directing the choreography for a new Broadway production of Kurt Weill’s Threepenny Opera, and creating a new solo dance for Mikhail Baryshnikov himself.