DALLAS -- San Antonio Spurs coach Gregg Popovich's pregame media availability Sunday opened with the NBA's all-time wins leader declining to discuss whether he would consider retirement this offseason and ended with an unprompted, passionate speech lobbying for gun control legislation in America and criticizing "cowardly legislators who are selfish." Popovich, 74, has expressed strong opinions on gun control and other political issues frequently in recent years. He made a point to bring up the subject as his media session before the Dallas Mavericks game seemed to be wrapping up, asking whether anyone in the room was carrying a firearm....