Changing Channels   Like a sleeping Elder God I have once again been roused to write a blog review. This past weekend I saw a preview performance of City Lit's production of John Reeger's Red Scare drama Changing Channels .   The usual disclaimers about my utter lack of objectivity: it's a preview which typically is not reviewed, and the show's star, Kat Evans, is my good friend and comfortably on my Favorite Humans of All Time list (currently accepting applications, the fee is a reasonable $35)    It's 1952, the dressing room of rising comedy star Maggie Carlin (Evans) on the set of a sketch comedy TV series that's about to be propelled to major success with an acquisition by CBS. Major praise goes to scenic designer Joe Larkin and costumer Emily McConnell for making the play's one setting period appropriate and fun to look at.    Evans is (objectivity be damned) absolutely glorious in how she captures Carlin's essence, the bold, brassy hilari...