BANNING (CNS) - A 21-year-old motorist accused of fatally hitting a bicyclist at a San Jacinto intersection, then fleeing the scene, was charged today with gross vehicular manslaughter.Savaughn JoJuan Colon Barnes of Hemet was arrested Sunday night following a Riverside County Sheriff's Department investigation into the death of 31-year-old Margarito Castro of San Jacinto.Along with the manslaughter count, Barnes was charged with a sentence- enhancing allegation of fleeing the scene of a crime.He was slated to make his initial court appearance Wednesday afternoon at the Banning Justice Center. The defendant is being held in lieu of $100,000 bail at the nearby Smith Correctional Facility.According to sheriff's Sgt. Dawn Blair, about 8 p.m. Sunday, Castro was in the center me