Allow to modify body after creation

Fixes: #16

Adds all missing methods that allow to modify a body after its creation.

New APIs:

Allows kinematic body to generate contact events when touching other kinematic or static objects.
```
entity.body.setCollideKinematicVsNonDynamic();
```
A gyroscopic force will be used on the body (aka Dzhanibekov effect)
```
entity.body.setApplyGyroscopicForce(true);
```

Clamps angular and linear velocities to their limits.

entity.body.clampAngularVelocity();
entity.body.clampLinearVelocity();

Resets motion of the body (previously body.resetVelocities()). Resets velocities, as well as forces and torques.
```
entity.body.resetMotion();
```

Sets a collision group

app.physics.createCollisionGroups([5]);
entity.body.setCollsionGroup(0, 3);

Allow better handling of collision with internal edges
```
entity.body.setEnhancedInternalEdgeRemoval(true)
```
Set clamped linear and angular velocities. They are similar to normal body.linearVelocity = vec3, but will make sure the final velocity is not over allowed limit.
```
entity.body.setLinearVelocityClamped(vec3);
entity.body.setAngularVelocityClamped(vec3);
```
Allow to override the default number of iterations a solver will use for this body - for velocity and for position.
```
entity.body.setNumPositionStepsOverride(5);
entity.body.setNumVelocityStepsOverride(10);
```

Gamebop / physics