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/generic/printps.h

@@ -19,6 +19,8 @@
 
 #include "wx/prntbase.h"
 
+#if wxUSE_PRINTING_ARCHITECTURE
+
 // ----------------------------------------------------------------------------
 // Represents the printer: manages printing a wxPrintout object
 // ----------------------------------------------------------------------------
@@ -62,5 +64,7 @@ private:
     void Init(wxPrintout *printout, wxPrintout *printoutForPrinting);
 };
 
+#endif
+
 #endif
 // __PRINTPSH__