rearranged order of including headers for compatibility with older boost/ Python versions

modules/gui/src/data_viewer/data_viewer.cc

@@ -33,9 +33,9 @@
 #include <ost/message.hh>
 //#include <ost/img/alg/fft.hh>   
 #include <ost/img/alg/norm.hh>   
+#include <ost/gui/gosty_app.hh>
 #include <ost/gui/dock_widget.hh>
 
-#include <ost/gui/gosty_app.hh>
 #include <ost/gui/perspective.hh>
 
 #include "data_viewer.hh"