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/stream.h

@@ -16,6 +16,10 @@
 #pragma interface
 #endif
 
+#include "wx/defs.h"
+
+#if wxUSE_STREAMS
+
 #include <stdio.h>
 #include "wx/object.h"
 #include "wx/string.h"
@@ -259,3 +263,7 @@ class WXDLLEXPORT wxFilterOutputStream: public wxOutputStream {
 };
 
 #endif
+  // wxUSE_STREAMS
+
+#endif
+  // _WX_WXSTREAM_H__