Robin Williams' son Zak shared a funny tribute to his father on Thursday, which would have been the actor's 71st birthday.The Good Will Hunting actor passed away in 2014 at age 63,by suicide at his home in Paradise Cay, California. His autopsy revealed undiagnosed Lewy body disease.'Happy 71st Birthday Dad! I'll be remembering you today as you would want to be remembered, in spandex.