One ship per day seems more realistic for the simulation (too much ships means they ends almost empty)

Need to create an empty commodity at the beginning otherwise commodities don't appear in list of species when simulation is running

Update according to new inheritance of network species + update some comments + don't need the get_path_time_length function for this purpose (too CPU consuming)

Update river shapefile + update several comments + add few lines to block canal seine nord at bigining of the simulation

Fisrt batch created inits the network + add some lines if I want to init less LSPs + link them with the correct provider according to attractiveness