Do not convert 'Type' value to string unnecessarily, and do not replace 'General' type with null

MediaBrowser.Controller/Providers/IExternalId.cs

@@ -20,6 +20,9 @@ namespace MediaBrowser.Controller.Providers
         /// <summary>
         /// Gets the specific media type for this id.
         /// </summary>
+        /// <remarks>
+        /// This can be used along with the <see cref="Name"/> to localize the external id on the client.
+        /// </remarks>
         ExternalIdMediaType Type { get; }
 
         /// <summary>

MediaBrowser.Model/Providers/ExternalIdInfo.cs

@@ -16,11 +16,12 @@ namespace MediaBrowser.Model.Providers
         public string Key { get; set; }
 
         /// <summary>
-        /// Gets or sets the media type (Album, Artist, etc).
-        /// This can be null if there is no specific type.
-        /// This string is also used to localize the media type on the client.
+        /// Gets or sets the specific media type for this id.
         /// </summary>
-        public string Type { get; set; }
+        /// <remarks>
+        /// This can be used along with the <see cref="Name"/> to localize the external id on the client.
+        /// </remarks>
+        public ExternalIdMediaType Type { get; set; }
 
         /// <summary>
         /// Gets or sets the URL format string.

MediaBrowser.Providers/Manager/ProviderManager.cs

@@ -908,7 +908,7 @@ namespace MediaBrowser.Providers.Manager
                 {
                     Name = i.Name,
                     Key = i.Key,
-                    Type = i.Type == ExternalIdMediaType.General ? null : i.Type.ToString(),
+                    Type = i.Type,
                     UrlFormatString = i.UrlFormatString
                 });
         }