A bunch of fixes to syncing clients who join mid-round:

- syncing items spawned/removed mid-round
- syncing characters spawned mid-round (through the console or by respawning)
- making sure that item IDs of the spawned characters match
- syncing wall damage

Subsurface/Source/Characters/AI/EnemyAIController.cs

@@ -435,6 +435,11 @@ namespace Barotrauma
             
             foreach (AITarget target in AITarget.List)
             {
+                if (Level.Loaded != null && target.WorldPosition.Y > Level.Loaded.Size.Y)
+                {
+                    continue;
+                }
+
                 float valueModifier = 0.0f;
                 float dist = 0.0f;