GLOBAL MARKETS-Shares gain after Bernanke comments, yields slip

* Bernanke flexible on timeline for stimulus program * Bank of America rises after strong profit growth * Euro falls 0.5 percent vs dollar, gold declines NEW YORK, July 17 (Reuters) - Stock markets around the world rose on Wednesday and U.S. Treasuries yields slipped after Federal Reserve Chairman Ben Bernanke said the timeline for the U.S. central bank to end its stimulus program was not set in stone. The dollar rose against the euro and yen while gold tumbled below $1,300 an