Code cleanup

Author: mfilippov

src/VimeoDotNet/VimeoClient_Folders.cs

@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.Net;
 using System.Net.Http;
-using System.Text;
 using System.Threading.Tasks;
 using VimeoDotNet.Constants;
 using VimeoDotNet.Exceptions;