Added wxRichToolTip class.

It can be used to show more customizable tooltips than the native wxToolTip
but at the price of using generic implementation in some cases (actually
almost always now, with the exceptions of text control tooltips under MSW).

Extra features include:
 - The balloon-like tooltip form.
 - Possibility to show an icon.
 - Title display in a different form.

More customization could be added later. It should be also possible to fully
implement this class natively under MSW.

Update the dialogs sample to show the rich tooltips in action.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@69463 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/private/richtooltip.h

@@ -0,0 +1,44 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        wx/private/richtooltip.h
+// Purpose:     wxRichToolTipImpl declaration.
+// Author:      Vadim Zeitlin
+// Created:     2011-10-18
+// RCS-ID:      $Id: wxhead.h,v 1.12 2010-04-22 12:44:51 zeitlin Exp $
+// Copyright:   (c) 2011 Vadim Zeitlin <vadim@wxwidgets.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_PRIVATE_RICHTOOLTIP_H_
+#define _WX_PRIVATE_RICHTOOLTIP_H_
+
+#include "wx/richtooltip.h"
+
+// ----------------------------------------------------------------------------
+// wxRichToolTipImpl: defines wxRichToolTip implementation.
+// ----------------------------------------------------------------------------
+
+class wxRichToolTipImpl
+{
+public:
+    // This is implemented in a platform-specific way.
+    static wxRichToolTipImpl* Create(const wxString& title,
+                                     const wxString& message);
+
+    // These methods simply mirror the public wxRichToolTip ones.
+    virtual void SetBackgroundColour(const wxColour& col,
+                                     const wxColour& colEnd) = 0;
+    virtual void SetCustomIcon(const wxIcon& icon) = 0;
+    virtual void SetStandardIcon(int icon) = 0;
+    virtual void SetTimeout(unsigned milliseconds) = 0;
+    virtual void SetTipKind(wxTipKind tipKind) = 0;
+    virtual void SetTitleFont(const wxFont& font) = 0;
+
+    virtual void ShowFor(wxWindow* win) = 0;
+
+    virtual ~wxRichToolTipImpl() { }
+
+protected:
+    wxRichToolTipImpl() { }
+};
+
+#endif // _WX_PRIVATE_RICHTOOLTIP_H_