DALLAS - The fountain at Fair Park echoed with the joyful giggles of children playing in the water, while adults sought refuge from the heat. It’s where CBS News Texas spoke with several people about being an American and pursuing the American dream.The Fourth of July seemed the proper time to ask Trevor, who withheld his last name, on the United States.”We live in the greatest country on the planet and the opportunity to go from the lowest income class society - norm, whatever - you have the same ability to move your way up,” he said. “It might take work. It…