FRANKFURT (Reuters) - Lufthansa vowed to step up up restructuring measures after posting a first-quarter net loss of 2.1 billion euros (1.87 billion pounds), days after agreeing a state bail-out amid the fallout from the coronavirus pandemic.The German carrier's pledge to slash costs comes as it braces for a significant decline in 2020 earnings."In view of the very slow recovery in demand, we must now take far-reaching restructuring measures," said Chief Executive Carsten Spohr, adding the..