Allow NoDelegate to **really** do nothing

src/kOS.Safe/Encapsulation/KOSDelegate.cs

@@ -62,7 +62,7 @@ public List<Structure> GetMergedArgs(List<Structure> args)
             return merged;
         }
 
-        public Structure CallPassingArgs(params Structure[] args)
+        public virtual Structure CallPassingArgs(params Structure[] args)
         {
             if (Cpu == null)
                 throw new KOSCannotCallException();

src/kOS.Safe/Encapsulation/NoDelegate.cs

@@ -1,16 +1,10 @@
-using System;
-using System.Collections.Generic;
 using kOS.Safe.Execution;
-using kOS.Safe.Exceptions;
-using kOS.Safe.Compilation;
 
 namespace kOS.Safe.Encapsulation
 {
     /// <summary>
-    /// A UserDelegate that cannot actually ever executesany user code.
-    /// Instead, when OpcodeCall() is executed for it, it will merely
-    /// crash with an exception.  The idea is to give scripts something
-    /// they can use to "unset" a callback hook.
+    /// A UserDelegate that cannot actually ever execute any user code.
+    /// The idea is to give scripts something they can use to "unset" a callback hook.
     /// </summary>
     [kOS.Safe.Utilities.KOSNomenclature("NoDelegate")]
     public class NoDelegate : UserDelegate
@@ -32,15 +26,10 @@ public override KOSDelegate Clone()
         {
             return new NoDelegate(Cpu);
         }
-
-        public override void PushUnderArgs()
-        {
-            // force it to do nothing.
-        }
-
-        public override Structure CallWithArgsPushedAlready()
+
+        public override Structure CallPassingArgs(params Structure[] args)
         {
-            throw new KOSCannotCallException();
+            return new KOSPassThruReturn();
         }
 
         public override string ToString()