fix(core): Fixes several serialization issues (#355)

- [X] Fixes an issue where a buffer smaller than 8 bytes would not double with enough space in some cases.
- [X] Fixes an issue with dupe copying the savebuffer reference (ugh).
- [X] Streamlines the IGenericWriter API to use better generics.
- [X] Streamlines the IGenericReader API to use better generics.
- [X] Forces `tidying` of a List/HashSet to be done externally since Writers/Readers should not have side effects.
- [X] Fixes an issue where Tidying a list didn't TrimExcess, causing memory leaks.
- [X] Reverted the meaning of `World.Running` to specifically refer to any world state post world loading.
  - NOTE: Do not use this if you want to block on world saves. Instead use checks against `WorldState.Saving` states.
- [X] Fixes an issue with serializing negative DateTime deltas.
- [X] Fixes a potential issue with serializing non-UTC DateTime.

Bumps release version

Projects/Server/Utilities/Utility.cs

@@ -1437,5 +1437,24 @@ namespace Server
 
             return string.Join(lineSeparator, parts);
         }
+
+        public static void Tidy<T>(this List<T> list) where T : ISerializable
+        {
+            for (int i = list.Count - 1; i >= 0; i--)
+            {
+                var entry = list[i];
+                if (entry?.Deleted != false)
+                {
+                    list.RemoveAt(i);
+                }
+            }
+
+            list.TrimExcess();
+        }
+
+        public static void Tidy<T>(this HashSet<T> set) where T : ISerializable
+        {
+            set.RemoveWhere(entry => entry?.Deleted != false);
+        }
     }
 }