By Justyna Pawlak and Yeganeh Torbati ALMATY (Reuters) - World powers and Iran failed again to end the deadlock in a decade-old dispute over Tehran's nuclear program in talks that ended in Kazakhstan on Saturday, prolonging a standoff that could yet spiral into a new Middle East war. No new talks were scheduled but big power negotiators, who earlier this year were insisting that time was running out, were at pains to say the diplomatic process would continue. Iran's critics accuse it of covertly seeking the means to produce nuclear bombs. ...