convert to new way of creating dialogs

gui/griffon-app/controllers/com/muwire/gui/AddContactController.groovy

@@ -41,6 +41,5 @@ class AddContactController {
     @ControllerAction
     void cancel() {
         view.dialog.setVisible(false)
-        mvcGroup.destroy()
     }
 }

gui/griffon-app/controllers/com/muwire/gui/MainFrameController.groovy

@@ -312,7 +312,7 @@ class MainFrameController {
     void addContact() {
         def params = [:]
         params.core = core
-        mvcGroup.createMVCGroup("add-contact", params)
+        mvcGroup.createMVCGroup("add-contact", params).destroy()
     }
     
     @ControllerAction

gui/griffon-app/views/com/muwire/gui/AddContactView.groovy

@@ -108,11 +108,6 @@ class AddContactView {
         dialog.pack()
         dialog.setLocationRelativeTo(mainFrame)
         dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE)
-        dialog.addWindowListener( new WindowAdapter() {
-            public void windowClosed(WindowEvent e) {
-                mvcGroup.destroy()
-            }
-        })
         dialog.show()
     }