Added OutOfBounds exception for DeleteMessages, for when Message Count is less than 2 or greater than 100

src/Discord.Net/Models/Channel.cs

@@ -204,6 +204,8 @@ namespace Discord
 
         public async Task DeleteMessages(ulong[] messageIds)
         {
+            if (messageIds.Count() < 2) throw new ArgumentOutOfRangeException("messageIds", "You must provide at least 2 Messages or Message Ids");
+
             await Client.ClientAPI.Send(new BulkMessageDelete(Id, messageIds));
         }