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/printqt.h

@@ -32,7 +32,7 @@ public:
     wxQtPrintPreview(wxPrintout *printout,
                           wxPrintout *printoutForPrinting,
                           wxPrintData *data);
-    
+
     virtual bool Print(bool interactive);
     virtual void DetermineScaling();