JERUSALEM (Reuters) - Israel imposed sanctions on the Gaza Strip and its dominant Hamas Islamists on Monday in retaliation for attacks by Palestinians using burning kites and helium balloons carrying blazing rags. People taking part in more than three months of protests at the Gaza border have started scores of fires by sending the balloons and kites into Israel, vexing its advanced military which is used to dealing with more conventional weapons. With southern residents and his far-right coalition partners calling for an end to the blazes, even if that required killing the kite- and balloon-fliers, Israeli Prime Minister Benjamin...