Add Blackboard support for Boolean

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Blackboard/BlackboardFieldPropertyView.cs

                 });
                 AddRow("Default", field);
             }
+            else if (property is BooleanShaderProperty)
+            {
+                var booleanProperty = (BooleanShaderProperty)property;
+                Action onBooleanChanged = () => 
+                { 
+                    booleanProperty.value = !booleanProperty.value;
+                    DirtyNodes();
+                };
+                var field = new Toggle(onBooleanChanged) { on = booleanProperty.value };
+                AddRow("Default", field);
+            }
 //            AddRow("Type", new TextField());
 //            AddRow("Exposed", new Toggle(null));
 //            AddRow("Range", new Toggle(null));

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Blackboard/BlackboardProvider.cs

             gm.AddItem(new GUIContent("Color"), false, () => AddProperty(new ColorShaderProperty(), true));
             gm.AddItem(new GUIContent("Texture"), false, () => AddProperty(new TextureShaderProperty(), true));
             gm.AddItem(new GUIContent("Cubemap"), false, () => AddProperty(new CubemapShaderProperty(), true));
+            gm.AddItem(new GUIContent("Boolean"), false, () => AddProperty(new BooleanShaderProperty(), true));
             gm.ShowAsContext();
         }