fix: use 'object' as default classification (#138)

The REST API operations that return collections of objects include a
classification property. Many nodes in the tree come back with a value
of "" for this property. However those nodes should be classified with
"object" instead. This is being resolved in the REST API; however this
commit addresses the issue when this client is used with older
unpatched Metasys devices.

MetasysServices/Models/MetasysObject.cs

@@ -82,6 +82,7 @@ public MetasysObject() { }
         /// Classification of the object
         /// </summary>
         public string Classification { get; set; }
+        private const string DefaultClassification = "object";
 
         internal MetasysObject(JToken token, ApiVersion version, IEnumerable<MetasysObject> children = null, MetasysObjectTypeEnum? type =null)
         {
@@ -187,11 +188,19 @@ internal MetasysObject(JToken token, ApiVersion version, IEnumerable<MetasysObje
             }
             try
             {
-                Classification = jobj.ContainsKey("classification") ? token["classification"].Value<string>() : null;
+                if (jobj.ContainsKey("classification")) 
+                {
+                    var tokenValue = token["classification"].Value<string>().Trim();
+                    Classification = tokenValue == string.Empty ? DefaultClassification : tokenValue;
+                }
+                else
+                {
+                    Classification = DefaultClassification;
+                }
             }
             catch
             {
-                Classification = null;
+                Classification = DefaultClassification;
             }
         }