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/clrpicker.h

@@ -57,7 +57,7 @@ class wxColourPickerCtrl : public wxPickerBase
 {
 public:
     wxColourPickerCtrl();
-    
+
     /**
         Initializes the object and calls Create() with all the parameters.
     */