perf(physics): air flowing along a pipe wakes the physics of a coupled vehicle only when it changes its pressure by more than physics.pipewake (0.001 bar), not with any trickle of it

utilities/Globals.h

@@ -116,6 +116,7 @@ struct global_settings {
     bool FullPhysics{ true }; // full calculations performed for each simulation step
     bool physics_sleepheld{ true }; // vehicles standing still and held by their brakes let their physics sleep, see TMoverParameters::accelerating()
     bool physics_roadlod{ true }; // road vehicles far from the camera go by one step of the physics in a frame, see vehicle_table::update()
+    float physics_pipewake{ 0.001f }; // bar: air flowing along a pipe wakes the physics of a vehicle when it changes its pressure by more than this. 0: any flow does
     bool bnewAirCouplers{ true };
     float fMoveLight{ 0.f }; // numer dnia w roku albo -1
     bool FakeLight{ false }; // toggle between fixed and dynamic daylight