Add output of first and last date

Overlap/report_graph.py

@@ -130,6 +130,16 @@ if __name__ == "__main__":
     n1 = len_H
     n2 = len_H
 
+    # First and last dates:
+    node_index = min(G.nodes)
+    my_date = node_to_date_eddy(node_index, G.graph["e_overestim"])\
+        ["date_index"]
+    print("First date:", my_date)
+    node_index = max(G.nodes)
+    my_date = node_to_date_eddy(node_index, G.graph["e_overestim"])\
+        ["date_index"]
+    print("Last date:", my_date)
+
     if args.merging:
         print("\nMerging:")