Fix potential order inconsistency of element and property lists.

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

@@ -0,0 +1,11 @@
+using System.Collections;
+using System.Collections.Generic;
+
+namespace Cryville.Common.Collections.Generic {
+	public interface IPairList : IList {
+		void Add(object key, object value);
+	}
+	public interface IPairList<TKey, TValue> : IList<KeyValuePair<TKey, TValue>>, IPairList {
+		void Add(TKey key, TValue value);
+	}
+}