Add tqdm to the main optimisation loop

main.py

@@ -523,7 +523,7 @@ n_iter = 3000
 loss_history_color, loss_history_sil = [], []
 
 # The main optimization loop.
-for iteration in range(n_iter):
+for iteration in tqdm(range(n_iter)):
     # In case we reached the last 75% of iterations,
     # decrease the learning rate of the optimizer 10-fold.
     if iteration == round(n_iter * 0.75):