Alan Cumming spent a busy day in Boston Monday. The Scottish actor, who stars on CBS’s “The Good Wife” and is currently reprising the role of the lascivious emcee in “Cabaret” on Broadway, began the afternoon at WGBH’s Calderwood Studio, taping a series of intros for the new season of “Masterpiece Mystery.” Then it was off to BU’s Howard Gotlieb Archival Research Center, where Cumming talked about his life and work. The actor was adorable as ever, even if The New York Times, in its review of “Cabaret,” called him a “little softer around the jaw.”