At last year’s Toronto International Film Festival, writer Ed Solomon was greeted by his past and his future at the same time. The festival was premiering his new film, “The Christophers,” directed by Steven Soderbergh, and was presenting a special anniversary screening of “Bill & Ted’s Excellent Adventure,” the 1989 sci-fi comedy that Solomon wrote with Chris Matheson (his first film, it effectively jump-started Solomon’s career). His first mov…