Updated reference channel entities

ref/Entities/IEntity.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Threading.Tasks;
+
+namespace Discord
+{
+    public interface IEntity<TId> : IEntity
+    {
+        /// <summary> Gets the unique identifier for this object. </summary>
+        TId Id { get; }
+    }
+    public interface IEntity
+    {
+        /// <summary> Gets the DiscordClient that manages this object. </summary>
+        DiscordClient Client { get; }
+        /// <summary> Gets the state of this object. </summary>
+        ModelState State { get; }
+
+        /// <summary> Deletes this object. </summary>
+        Task Delete();
+        /// <summary> Downloads the latest values and updates this object. </summary>
+        Task Update();
+    }
+}