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/private/notifmsg.h

@@ -66,7 +66,7 @@ protected:
     void SetActive(bool active)
     {
         m_active = active;
-        
+
         // Delete the implementation if the notification is detached
         if (!m_notification && !active)
             delete this;