Rigid motion chaining - check if `next` `id`s exist

[han16nah]

Problem Simulations with dynamic scenes composed of a sequence of rigid motions may suddenly stop if an id is used for chaining the motions (using the next parameter) which does not exist.

Solution Although the behaviour is expected, the following improvement could be made to facilitate debugging:

Introduce a check (before building the dynamic scene) if all ids specified with the next parameters exist. If not, raise a warning/error and abort the simulation right away.