By Arathy Somasekhar HOUSTON (Reuters) – Protesters holding signs and crosses with photos of victims from this week’s Texas elementary school shooting, converged Friday outside the gun lobby National Rifle Association’s annual convention in Houston. About 500 protesters, some shouting “NRA go away,” and “Shame, it could be your kids today,” jeered as thousands of members of the nation’s biggest gun lobby thronged the conventional center. Tuesday’s fatal shooting of 19 Uvalde, Texas, students and two teachers by an 18-year-old gunman equipped with an AR-15 style semiautomatic assault rife is ex…