Update JsonFunctions.cs

I was able to workaround the U-SQL string limit issue for nested JSONs by using JsonTuple<byte[]>(json)

Examples/DataFormats/Microsoft.Analytics.Samples.Formats/Json/JsonFunctions.cs

@@ -16,6 +16,7 @@
 using System;
 using System.Linq;
 using System.Collections.Generic;
+using System.Text;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 using Microsoft.Analytics.Types.Sql;
@@ -146,6 +147,11 @@ namespace Microsoft.Analytics.Samples.Formats.Json
                 {
                     return JsonFunctions.GetTokenString(token);
                 }
+                else if(type == typeof(byte[]))
+                {
+                    //Workaround to U-SQL string limit issue for nested JSONs
+                    return Encoding.UTF8.GetBytes(JsonFunctions.GetTokenString(token));
+                }
             
                 // We simply delegate to Json.Net for data conversions
                 return token.ToObject(type);