Wrap angles to (-pi, pi) in momentum calculation.

Fixes a bug that causes KinematicBody2Ds to produce too much angular
momentum when rotating beyond 180 degrees.

servers/physics_2d/body_2d_sw.cpp

@@ -468,7 +468,7 @@ void Body2DSW::integrate_forces(real_t p_step) {
 		linear_velocity = motion / p_step;
 
 		real_t rot = new_transform.get_rotation() - get_transform().get_rotation();
-		angular_velocity = rot / p_step;
+		angular_velocity = remainder(rot, 2.0 * Math_PI) / p_step;
 
 		do_motion = true;