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/rearrangectrl.h

@@ -301,7 +301,7 @@ public:
 
     /**
         Effectively creates the dialog for an object created using the default
-        constructor. 
+        constructor.
 
         @param parent
             The dialog parent, possibly @NULL.