By Kiyoshi Takenaka and Chris Gallagher WAJIMA, Japan (Reuters) -Thousands of rescuers pressed on in their search for survivors of a New Year’s Day earthquake that killed at least 81 people in Japan, hoping to save as many as possible within a three day survival window that ends on Thursday afternoon. “There are many people left behind in the collapsed buildings, waiting to be rescued,” Japanese Prime Minister Fumio Kishida said at a press conference. “We will use all of our efforts to rescue as many people as possible by this evening, when 72 hours will pass since the disaster,” he said. Surv…