Added new stocking scope to shader gui;

Added new stocking surface feature;
Added unity 6.3 support;

Fixed the issue that ssr weight does not blend ibl and ssr properly;
Fixed the issue that material recive ssr regardless of specular ambient mode;

Editor/MeterialEditor/UIScopes/AdvanceScope.cs

@@ -6,7 +6,7 @@ using static Misaki.HdrpToon.UTSPropertyName.Advance;
 
 namespace Misaki.HdrpToon.Editor
 {
-    public class AdvanceScope : MaterialUIScope<ShaderGUIExpandable>
+    internal class AdvanceScope : MaterialUIScope<ShaderGUIExpandable>
     {
         private static class Properties
         {
@@ -32,7 +32,7 @@ namespace Misaki.HdrpToon.Editor
 
         protected override GUIContent Header => EditorGUIUtility.TrTextContent("Advance Settings");
 
-        public override void LoadMaterialProperties()
+        protected override void LoadMaterialProperties()
         {
             Properties.diffuseMin = FindProperty(MINIMAL_DIFFUSE_CONTRIBUTION);