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/filesys.h

@@ -64,7 +64,7 @@ public:
        Remove a filesystem handler from the list of handlers.
     */
     static wxFileSystemHandler* RemoveHandler(wxFileSystemHandler *handler);
-    
+
     /**
         Sets the current location. @a location parameter passed to OpenFile() is
         relative to this path.