Remove all trailing spaces

No real changes, just clean up sources by removing trailing spaces from
all the non-generated files.

This should hopefully avoid future commits mixing significant changes
with insignificant whitespace ones.

include/wx/qt/statbox.h

@@ -14,7 +14,7 @@ class WXDLLIMPEXP_CORE wxStaticBox : public wxStaticBoxBase
 {
 public:
     wxStaticBox();
-    
+
     wxStaticBox(wxWindow *parent, wxWindowID id,
                 const wxString& label,
                 const wxPoint& pos = wxDefaultPosition,