1- namespace credal

2- renommer MCSampling -> CNMonteCarloSampling

3- CNInferenceEngine vs. CNInferenceEngines ??

4- attribut like mySomeThing ??

5- OMPThread not in core ?? in gum_thread namespace ?? 
  => in core
  => in gum::omp namesapce (non ?)

6- Ajouter les headers (licence+Authors) aux fichiers