Hip-hop has been firmly in the mainstream for decades when it comes to music, but less so when it comes to dance. Hip-hop and street dance styles rarely get the rarefied treatment of forms like ballet and modern. This weekend, however, hip-hop gets the fine art approach at Orange County’s Segerstrom Center for the Arts. Choreographer Amy O’Neal has created a theater piece featuring five B-boys from different street crews in Seattle, and it runs this Thursday through Saturday as part of the Segerstrom’s fourth annual Off-Center Festival. She discusses her work.