By Tom Miles GENEVA (Reuters) - The United Nations gave its starkest warning yet on Friday that it would soon run out of cash to cope with the vast influx of Syrian refugees into Jordan and other neighboring countries. "The needs are rising exponentially, and we are broke," Marixie Mercado, spokeswoman for the U.N. Children's Fund UNICEF, told a U.N. news conference in Geneva. The number of people fleeing in the world's worst refugee crisis has repeatedly outrun the U.N.'s expectations. The 1. ...