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.

interface/wx/aui/tabmdi.h

@@ -108,7 +108,7 @@ public:
                                      wxWindowID winid,
                                      const wxString& name);
     virtual wxToolBar *GetToolBar() const;
-    
+
     // no maximize etc
     virtual void Maximize(bool maximize = true);
     virtual void Restore();