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

Create a new scenario to automatically block some roads at steps 500 and 1000 (useful to generate videos)