MechanicalObject
----------------

Context: Sofa.Component.StateContainer

mechanical state vectors

Data:
 - name : object name
 - printLog : if true, emits extra messages at runtime.
 - tags : list of the subsets the objet belongs to
 - bbox : this object bounding box
 - componentState : The state of the component among (Dirty, Valid, Undefined, Loading, Invalid).
 - listening : if true, handle the events, otherwise ignore the events
 - position : position coordinates of the degrees of freedom
 - velocity : velocity coordinates of the degrees of freedom
 - force : force vector of the degrees of freedom
 - rest_position : rest position coordinates of the degrees of freedom
 - externalForce : externalForces vector of the degrees of freedom
 - derivX : dx vector of the degrees of freedom
 - free_position : free position coordinates of the degrees of freedom
 - free_velocity : free velocity coordinates of the degrees of freedom
 - constraint : constraints applied to the degrees of freedom
 - mappingJacobian : mappingJacobian applied to the degrees of freedom
 - reset_position : reset position coordinates of the degrees of freedom
 - reset_velocity : reset velocity coordinates of the degrees of freedom
 - restScale : optional scaling of rest position coordinates (to simulated pre-existing internal tension).(default = 1.0)
 - useTopology : Shall this object rely on any active topology to initialize its size and positions
 - showObject : Show objects. (default=false)
 - showObjectScale : Scale for object display. (default=0.1)
 - showIndices : Show indices. (default=false)
 - showIndicesScale : Scale for indices display. (default=0.02)
 - showVectors : Show velocity. (default=false)
 - showVectorsScale : Scale for vectors display. (default=0.0001)
 - drawMode : The way vectors will be drawn:
- 0: Line
- 1:Cylinder
- 2: Arrow.

The DOFS will be drawn:
- 0: point
- >1: sphere. (default=0)
 - showColor : Color for object display. (default=[1 1 1 1])
 - translation : Translation of the DOFs
 - rotation : Rotation of the DOFs
 - scale3d : Scale of the DOFs in 3 dimensions
 - translation2 : Translation of the DOFs, applied after the rest position has been computed
 - rotation2 : Rotation of the DOFs, applied the after the rest position has been computed
 - size : Size of the vectors
 - reserve : Size to reserve when creating vectors. (default=0)

Links:
 - context : Graph Node containing this object (or BaseContext::getDefault() if no graph is used
 - slaves : Sub-objects used internally by this object
 - master : nullptr for regular objects, or master object for which this object is one sub-objects
 - topology : Link to the topology relevant for this object