Added some (commented out) debug lines that are useful when comparing

different kart physics.

src/karts/kart.cpp

@@ -1093,6 +1093,19 @@ void Kart::eliminate()
  */
 void Kart::update(float dt)
 {
+#ifdef DEBUG_TO_COMPARE_KART_PHYSICS
+    // This information is useful when comparing kart physics, e.g. to
+    // see top speed, acceleration (i.e. time to top speed) etc.
+    Log::verbose("physics", "%s t %f xyz %f %f %f %f v %f %f %f %f maxv %f",
+        getIdent().c_str(),
+        World::getWorld()->getTime(),
+        getXYZ().getX(), getXYZ().getY(), getXYZ().getZ(),
+        getXYZ().length(),
+        getVelocity().getX(), getVelocity().getY(), getVelocity().getZ(),
+        getVelocity().length(),
+        m_max_speed->getCurrentMaxSpeed());
+#endif
+
     if ( UserConfigParams::m_graphical_effects )
     {
         // update star effect (call will do nothing if stars are not activated)