Non-profit research and advocacy centre in Ottawa heritage building will promote diversity and tolerance The Aga Khan returned Tuesday to Ottawa to unveil the new headquarters of an international organization that is positioning itself as an antidote of sorts to growing strains of populism and intolerance around the world. But if you thought for one minute that the wealthy philanthropist, who is hereditary spiritual leader to the world's 15 million Ismaili Muslims, would talk about that helicopter ride he gave to Justin Trudeau over the Christmas holidays, forget it. The 80-year-old Aga Khan kept the focus on the opening of the new home for the Global Centre for Pluralism — part think tank, part advocacy group — in a renovated piece of prime Ottawa real estate on Sussex Drive. John McNee, secretary…