KAFR YASIF, Israel (AP) — Nabil Safiya had taken a break from studying for a biology exam to meet a cousin at a pizza parlor when a gunman on a motorcycle rode past and fired, killing the 15-year-old as he sat in a black Renault. The shooting — which police later said was a case of mistaken identity — stunned his hometown of Kafr Yasif, long besieged, like many Palestinian towns in Israel, by a wave of gang violence and family feuds. “There is no set time for the gunfire anymore,” said Nabil’s