opengl.geometry: Add subprograms to get and set the model.

3-mid/opengl/source/lean/geometry/opengl-geometry.adb

@@ -57,6 +57,12 @@ is
    end Model_is;
 
 
+   function Model (Self : in Item) return Model_view
+   is
+   begin
+      return Self.Model;
+   end Model;
+
 
 
    function Label (Self : in Item'Class) return String

3-mid/opengl/source/lean/geometry/opengl-geometry.ads

@@ -45,7 +45,7 @@ is
    type Model_view is access all openGL.Model.item'Class;
 
    procedure Model_is (Self : in out Item;   Now : in Model_view);
-
+   function  Model    (Self : in     Item)     return Model_view;
 
    procedure Label_is        (Self : in out Item'Class;   Now : in String);
    function  Label           (Self : in     Item'Class)     return String;