VENICE, Italy — President Reagan, who less than two years ago signed the most expensive farm aid bill in history, called Friday for the elimination of agricultural subsidies worldwide by the year 2000 as a way of promoting better world economic health.At the same time, Reagan said that the United States has made "real progress" in trimming its budget deficit, despite ongoing spending battles with Congress, thereby freeing for private investment abroad some of the foreign capital that has been tied up financing the U.S. debt.Reagan's remarks, made in a speech televised by Worldnet and provided to networks around the...