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/protocol/protocol.h

@@ -132,7 +132,7 @@ public:
 
     /**
         Detach the existing logger without deleting it.
-        
+
         The caller is responsible for deleting the returned pointer if it's
         non-@c NULL.
      */