add IsOk() to all classes having Ok() method (patch 1570985)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41751 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/image.h

@@ -327,7 +327,8 @@ public:
     virtual bool SaveFile( wxOutputStream& stream, const wxString& mimetype ) const;
 #endif
 
-    bool Ok() const;
+    bool Ok() const { return IsOk(); }
+    bool IsOk() const;
     int GetWidth() const;
     int GetHeight() const;