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/file.h

@@ -22,6 +22,8 @@
   #include  "wx/filefn.h"
 #endif
 
+#if wxUSE_FILE
+
 // ----------------------------------------------------------------------------
 // constants
 // ----------------------------------------------------------------------------
@@ -178,5 +180,7 @@ private:
   wxFile    m_file;     // the temporary file
 };
 
+#endif
+
 #endif
         // _WX_FILEH__