LONDON (Reuters) - World shares staged a cautious rally on Monday as investors held out for some progress in U.S.-China trade talks, while the dollar dipped after its latest rally on the back of strong U.S. economic data.The MSCI All-Country World Index , which tracks shares across 47 countries, was up 0.2% by midday in London.European shares rose for the second straight session following reports that Washington and Beijing were nearing a trade agreement. The pan-European STOXX 600 index was up..