SAN DIEGO (Reuters) - Donald Trump brought his message of walls and deportations to the doorstep of America’s busiest border crossing on Friday as the presumptive Republican presidential nominee greeted supporters in San Diego, amid one of the largest counter-protests organized against him. The scene inside the San Diego Convention Center during Trump's speech was relatively placid, while outside demonstrators opposed to his controversy-ridden White House bid marched and chanted, carrying signs criticizing his rhetoric against illegal immigration. Waving U.S. and Mexican flags, more than 1,000 people turned out for anti-trump rallies in San Diego, a city on the U.S.-Mexico...