Furious foodies are at  tipping  point.  Publicly shaming patrons into leaving hefty tips for waiters is, apparently, not the slam-dunk strategy one restauranteur had hoped it would be. Now, cheesed-off chowhounds are viciously, virally blasting the boneheaded boss for bullying customers to pay his staff a decent salary.  “Our servers make $3.50 [per hour]…If you can’t afford to tip, you can’t afford to dine out,” reads a bulletin crudely taped to the window of unidentified eatery. In New York,