Moved MapEntity saving methods to the shared project (the server needs to be able to save subs in the campaign mode)

Barotrauma/BarotraumaShared/Source/Items/Components/Signal/Connection.cs

@@ -1,4 +1,5 @@
 using Microsoft.Xna.Framework;
+using System;
 using System.Collections.Generic;
 using System.Xml.Linq;
 
@@ -205,5 +206,27 @@ namespace Barotrauma.Items.Components
             }
         }
 
+
+        public void Save(XElement parentElement)
+        {
+            XElement newElement = new XElement(IsOutput ? "output" : "input", new XAttribute("name", Name));
+
+            Array.Sort(Wires, delegate (Wire wire1, Wire wire2)
+            {
+                if (wire1 == null) return 1;
+                if (wire2 == null) return -1;
+                return wire1.Item.ID.CompareTo(wire2.Item.ID);
+            });
+
+            for (int i = 0; i < MaxLinked; i++)
+            {
+                if (Wires[i] == null) continue;
+                
+                newElement.Add(new XElement("link",
+                    new XAttribute("w", Wires[i].Item.ID.ToString())));
+            }
+
+            parentElement.Add(newElement);
+        }
     }
 }