- multiple submarines can be "merged" into one file (to be used as escape vessels etc)

- WIP docking ports

Subsurface/Source/Items/Item.cs

@@ -1432,7 +1432,7 @@ namespace Barotrauma
             return true;
         }
        
-        public override XElement Save(XDocument doc)
+        public override XElement Save(XElement parentElement)
         {
             XElement element = new XElement("Item");
 
@@ -1475,7 +1475,7 @@ namespace Barotrauma
                 ic.Save(element);
             }
 
-            doc.Root.Add(element);
+            parentElement.Add(element);
 
             return element;
         }