Update depth property description and default value returned by query.depth()

Author: rboulton-BH

XML_Engine/Query/Depth.cs

@@ -43,13 +43,13 @@ public static partial class Query
         /**** Public Methods                            ****/
         /***************************************************/
 
-        [Description("Returns the 'depth' property of a markup object as a double. If the value cannot be converted to a double (if the value is null or blank for example) then an error will be provided and -1 will be returned.")]
+        [Description("Returns the 'depth' property of a markup object as a double. If the value cannot be converted to a double (if the value is null or blank for example) then an error will be provided and 0 will be returned.")]
         [Input("markup", "A markup object which contains the 'depth' property.")]
-        [Output("depth", "The depth value as a double, or -1 if the value could not be converted to a double.")]
+        [Output("depth", "The depth value as a double, or 0 if the value could not be converted to a double.")]
         public static double Depth(this Markup markup)
         {
             if (markup == null)
-                return -1;
+                return 0;
 
             try
             {
@@ -58,7 +58,7 @@ public static double Depth(this Markup markup)
             catch (Exception e)
             {
                 BH.Engine.Base.Compute.RecordError($"Could not convert XMLDepth value {markup.Depth} to numerical depth.");
-                return -1;
+                return 0;
             }
         }
     }

XML_oM/Bluebeam/BluebeamObject.cs

@@ -34,7 +34,7 @@ namespace BH.oM.XML.Bluebeam
     public class BluebeamObject : IBHoMObject
     {
         [XmlIgnore]
-        public virtual Guid BHoM_Guid { get; set; }
+        public virtual Guid BHoM_Guid { get; set; } = Guid.NewGuid();
         [XmlIgnore]
         public virtual Dictionary<string, object> CustomData { get; set; }
         [XmlIgnore]

XML_oM/Bluebeam/Markup.cs

@@ -22,6 +22,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
@@ -64,6 +65,7 @@ public class Markup : BluebeamObject
         [XmlElement("Label")]
         public virtual string Label { get; set; }
 
+        [Description("By default this is an XML String representation. Most software will automatically handle the conversion to a numerical representation but users can also use the Query.Depth(Markup) method if necessary.")]
         [XmlElement("Depth")]
         public virtual string Depth { get; set; }