By Andrew Mills DOHA (Reuters) -Qatar has faced unprecedented criticism since winning the bid to host the 2022 World Cup, some of which amounted to slander, its ruler, Emir Sheikh Tamim bin Hamad al-Thani, said on Tuesday. “We initially dealt with the matter in good faith,” Sheikh Tamim said in a televised policy speech, adding that some of the early criticism was constructive. But, he said, a campaign against Qatar expanded to “include fabrications and double standards that were so ferocious that it has unfortunately prompted many people to question the real reasons and motives behind the cam…