Added a few #if wxUSE_XXX

Regrouped image format handlers
  Updated the rest accordingly
  Added changes.txt for wxGTK


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@2795 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/datstrm.h

@@ -18,6 +18,8 @@
 
 #include <wx/stream.h>
 
+#if wxUSE_STREAMS
+
 class WXDLLEXPORT wxDataInputStream: public wxFilterInputStream {
 public:
   wxDataInputStream(wxInputStream& s);
@@ -44,5 +46,8 @@ class WXDLLEXPORT wxDataOutputStream: public wxFilterOutputStream {
   void WriteString(const wxString& string);
 };
 
+#endif
+  // wxUSE_STREAMS
+
 #endif
     // _WX_DATSTREAM_H_