Agence France-Presse: Avatar director James Cameron vowed Friday to fight on for the indigenous people of the Amazon after a Brazilian court overturned a ruling that would have halted construction of a huge dam that would flood tribal lands. “We are disappointed but we knew this would be a long battle,” Cameron told AFP by phone during a brief visit to Washington. “If Brazil lets me back in, I would love to come back down and work with the indigenous people I met” during several visits to the vast …