Ajout de la possibilité de rentrer une valeur constante (int ou float) à la place d'une série temporelle pour l'attribut p (power) d'une FixedEnergyUnit 

[Replacing "indexes" by "indices" in model due to PuLP update (and updating PuLP version requirements accordingly)]

[Removing pc and pd max warnings when not defined: already printed and not needed when using minimize capacity]

Debug if pdmax assigned alone