Change output key to solution

stats-config.json

@@ -22,7 +22,7 @@
                 "filetype": "ufm"
             }
         },
-        "output": {
+        "solution": {
             "args": {
                 "filetype": "ufs"
             }
@@ -44,7 +44,7 @@
                 "file": "Exmouth_Network.dat",
                 "gis-file": "Exmouth_Network.gis"
             },
-            "output": {
+            "solution": {
                 "file": "Exmouth_Network.UFS"
             },
             "demand": {
@@ -57,7 +57,7 @@
                 "file": "Exmouth_Network_x3Congestion.dat",
                 "gis-file": "Exmouth_Network.gis"
             },
-            "output": {
+            "solution": {
                 "file": "Exmouth_Network_x3Congestion.UFS"
             },
             "demand": {
@@ -70,7 +70,7 @@
                 "file": "Exmouth_Network_x5Congestion.dat",
                 "gis-file": "Exmouth_Network.gis"
             },
-            "output": {
+            "solution": {
                 "file": "Exmouth_Network_x5Congestion.UFS"
             },
             "demand": {