Add GStreamer plugin ranking to preferences

clapper_src/prefsBase.js

@@ -1,4 +1,7 @@
 const { Gio, GObject, Gtk } = imports.gi;
+const Debug = imports.clapper_src.debug;
+
+let { debug } = Debug;
 
 var Notebook = GObject.registerClass(
 class ClapperPrefsNotebook extends Gtk.Notebook
@@ -41,6 +44,18 @@ class ClapperPrefsNotebook extends Gtk.Notebook
         });
         this.append_page(widget, label);
     }
+
+    _onClose()
+    {
+        let totalPages = this.get_n_pages();
+        let index = 0;
+
+        while(index < totalPages) {
+            let page = this.get_nth_page(index);
+            page._onClose();
+            index++;
+        }
+    }
 });
 
 var Grid = GObject.registerClass(
@@ -168,4 +183,10 @@ class ClapperPrefsGrid extends Gtk.Grid
 
         return checkButton;
     }
+
+    _onClose(name)
+    {
+        if(name)
+            debug(`cleanup of prefs ${name} page`);
+    }
 });