Performance optimization. — Armored Battalion Steam update #988561

1. Performance optimization. 2. Replace the camera with a top-down view. Additional: The original intention is to do large-scale battles, but the current performance situation can only support up to 200 tanks, that is, the battle in the demo is the largest scale, and the top-down view will greatly improve the performance, but there will be some insufficient information because the view is not as far as before,