On Sunday night, actors Nathan Fillion and Sean Maher, along with costume designer Shawna Trpcic, cryptically tweeted a link to a Web page featuring a photo of Fillion toting a martini glass, somewhere in the middle of a lake. The image announced the completion of a new movie from Joss Whedon, the genius whose “Buffy the Vampire Slayer,” “Angel,” “Dr. Horrible’s Sing-Along Blog,” “Firefly” and, to a lesser extent, “Dollhouse” are the very definition of awesome to nerds everywhere. According to the clues, the film stars a veritable who’s who of Whedon alums. And it’s “based on a play.” A Shakespeare play. Oh God. Ohmigod. Then on Monday, Bellwether Pictures officially announced Whedon’s “Much Ado About Nothing.” That thud you heard was everybody in America with a liberal arts degree fainting dead in excitement.