Fix potential order inconsistency of element and property lists.

Assets/Cryville/Common/Collections/Generic/PairCollection.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections;
+
+namespace Cryville.Common.Collections.Generic {
+	public struct PairCollection : IDisposable {
+		public void Dispose() { }
+		IPairList _pairList;
+		IDictionary _dictionary;
+		public PairCollection(object collection) : this() {
+			var type = collection.GetType();
+			if (typeof(IPairList).IsAssignableFrom(type)) _pairList = (IPairList)collection;
+			else if (typeof(IDictionary).IsAssignableFrom(type)) _dictionary = (IDictionary)collection;
+			else throw new ArgumentException("Parameter is not a pair collection");
+		}
+		public void Add(object key, object value) {
+			if (_pairList != null) _pairList.Add(key, value);
+			else _dictionary.Add(key, value);
+		}
+	}
+}