Update job

that was actually my main problem with the old way of doing things. sure, we could do a placeholder object and fill-in all functions but we lose flexibility. here i just spawn one job and it's up to the developer to do whatever he thinks useful to him (why not do everything in one job if he needs it, no ?). personnaly I'll stick with it for now, it's open for discussion later, especially if we transcribe it to an api but I don't think that's bad design to let the developer some freedom.