1. minor fixes in wxDynLib

2. added more symbols to winundef.h
3. fixed wxTextFile::IsOpen() - now it does what you'd suppose
4. listctrl now updates the item image when it changes
5. file dlg checks for an error and gives a message about it (debug only)


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@2973 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/textfile.h

@@ -63,7 +63,7 @@ public:
     // closes the file and frees memory, losing all changes
   bool Close();
     // is file currently opened?
-  bool IsOpened() const { return m_file.IsOpened(); }
+  bool IsOpened() const { return m_isOpened; }
 
   // accessors
     // get the number of lines in the file
@@ -137,6 +137,8 @@ private:
 
   size_t        m_nCurLine; // number of current line in the file
 
+  bool          m_isOpened; // was the file successfully opened the last time?
+
   wxString      m_strFile;  // name of the file
 };