fix regressions with sleeping behavior of kinematic bodies (#885)

* fix kinematic bodies ignoring the wake_up flag when setting velocities

* fix: don’t allow kinematic bodies to fall asleep unless they velocities are at zero exactly.

* feat: add debug example for kinematic bodies sleep

* chore: update changelog

* chore: typo

examples3d/all_examples3.rs

@@ -44,6 +44,7 @@ mod debug_cube_high_mass_ratio3;
 mod debug_internal_edges3;
 mod debug_long_chain3;
 mod debug_multibody_ang_motor_pos3;
+mod debug_sleeping_kinematic3;
 mod gyroscopic3;
 mod inverse_kinematics3;
 mod joint_motor_position3;
@@ -132,6 +133,10 @@ pub fn main() {
             "(Debug) shape modification",
             debug_shape_modification3::init_world,
         ),
+        (
+            "(Debug) sleeping kinematics",
+            debug_sleeping_kinematic3::init_world,
+        ),
         ("(Debug) deserialize", debug_deserialize3::init_world),
         (
             "(Debug) multibody ang. motor pos.",