Remove unnecessary usings

Author: ellemayo

jQueryFileUpload/Upload.ashx.cs

@@ -1,9 +1,7 @@
-using System;
 using System.Collections.Generic;
-using System.Linq;
+using System.IO;
 using System.Web;
 using System.Web.Script.Serialization;
-using System.IO;
 
 namespace WebInterface.General.Handlers
 {