John Kocur, photo by Veronika LukasovaUp-and-coming local jazz musician John Kocur is carving out a niche as a versatile player who can fit into a number of situations. In addition to leading his own group, which released its first album last year, the saxophonist plays with a number of other artists around town. Notably, he performs regularly with rapper, Grammy nominee, and Three Stars alum Christylez. The two musicians have a special gig coming…