Agence France-Presse: Australia’s second-largest city Melbourne was struggling to cope Saturday with a once-in-a-century heatwave that has claimed dozens of lives and sparked wildfires that have razed up to 20 homes. More than 500,000 houses and businesses in the city of five million were left without power on Friday night after an electrical substation exploded in the heat. Emergency services were stretched to breaking point as dozens of people succumbed to heat-induced …