Added some parts of ctk lib.

As it looks now that lib contains way more then I want to pull in so i'm just copying the files i'm interested in.

ctk/ctkPopupWidget_p.h

@@ -0,0 +1,67 @@
+/*=========================================================================
+
+  Library:   CTK
+
+  Copyright (c) Kitware Inc.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0.txt
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+=========================================================================*/
+
+#ifndef __ctkPopupWidget_p_h
+#define __ctkPopupWidget_p_h
+
+// CTK includes
+#include "ctkBasePopupWidget_p.h"
+#include "ctkPopupWidget.h"
+
+// -------------------------------------------------------------------------
+/// \ingroup Widgets
+class CTK_WIDGETS_EXPORT ctkPopupWidgetPrivate
+  : public ctkBasePopupWidgetPrivate
+{
+  Q_OBJECT
+  Q_DECLARE_PUBLIC(ctkPopupWidget);
+public:
+  typedef ctkBasePopupWidgetPrivate Superclass;
+  ctkPopupWidgetPrivate(ctkPopupWidget& object);
+  ~ctkPopupWidgetPrivate();
+
+  virtual void init();
+
+  // Return the widget if the mouse cursor is above any of the focus widgets or their
+  // children.
+  // If the cursor is above a child widget, install the event filter to listen
+  // when the cursor leaves the widget.
+  virtual QWidget* mouseOver();
+
+  virtual bool eventFilter(QObject* obj, QEvent* event);
+
+  void temporarilyHiddenOn();
+  void temporarilyHiddenOff();
+
+  bool isHidingCandidate(QWidget* widget)const;
+
+public Q_SLOTS:
+  void updateVisibility();
+  void onApplicationDeactivate();
+
+protected:
+  bool Active;
+  bool AutoShow;
+  int  ShowDelay;
+  bool AutoHide;
+  int  HideDelay;
+};
+
+#endif