Implemented functionality to exclude a class from generating a menu item

Author: pschraut

Editor/ScriptableObjectContainerEditor.cs

@@ -609,6 +609,8 @@ void GetScriptableObjectTypes(List<System.Type> result)
                                 continue;
                             if (!a.allowSubClass && t != a.type)
                                 continue;
+                            if (a.excludeThisClass && t == a.type)
+                                continue;
                             supportsType = true;
                             break;
                         }

Runtime/Attributes/CreateSubAssetMenuAttribute.cs

@@ -35,6 +35,17 @@ public bool allowSubClass
             set;
         }
 
+        /// <summary>
+        /// Whether to create a menu item for the <see cref="type"/> specifically. It's useful when you add
+        /// the <see cref="CreateSubAssetMenuAttribute"/> to a base-class where you want all sub-classes to
+        /// have menu items generated for, except for the base-class.
+        /// </summary>
+        public bool excludeThisClass
+        {
+            get;
+            set;
+        }
+
         /// <summary>
         /// The display name for this type shown in the "Add Object" menu.
         /// If <see cref="menuName"/> is empty, it uses the type name instead.