SAN ANTONIO – For the longest time, the San Antonio Spurs seemed so full of precision, so superior, so . . . invincible. Fifty days. That’s how long the Spurs went without losing a game. Before them, only three teams in NBA history had winning streaks of 20 or more games. They became the fourth. Included in that streak was eight straight in the playoffs. That number stretched to 10 when the Spurs handled the Thunder without significant problems in the first