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/dcpsg.h

@@ -17,6 +17,8 @@
 
 #include "wx/dc.h"
 
+#if wxUSE_PRINTING_ARCHITECTURE
+
 #if wxUSE_POSTSCRIPT
 
 #include "wx/dialog.h"
@@ -275,6 +277,9 @@ WXDLLEXPORT extern void wxInitializePrintSetupData(bool init = TRUE);
 
 #endif
     // wxUSE_POSTSCRIPT
+    
+#endif
+    // wxUSE_PRINTING_ARCHITECTURE
 
 #endif
         // _WX_DCPSG_H_