New musicals, old classics, stories about soda…April’s theater selections run the gamut. Taffety Punk’s armed with their new premiere, The Faithkiller (April 1). Nurse Ratchett’s on the loose over at Round House, where they’re performing One Flew Over The Cuckoo’s Nest (April 1). Sharpen your swords (and your wits) to take in Georgetown Theatre Company’s production of The Three Musketeers (April 4). Landless takes a stab at everyone’s favorite retail target (no capitals intentional)…