Tillerson ends China trip with warm words from President Xi

By Yeganeh Torbati and Michael MartinaBEIJING (Reuters) - With warm words from Chinese President Xi Jinping on Sunday, U.S. Secretary of State Rex Tillerson ended his first trip to Asia since taking office with an agreement to work together with China on North Korea and putting aside trickier issues.China has been irritated at being repeatedly told by Washington to rein in North Korea's nuclear and missile programs and the U.S. decision to base an advanced missile defense system in South Korea.B