usability tweaks: functions that return iterators return them as *const* to allow chaining when the recipient function expects a reference (e.g. foo(Iter&) )

[SVN r35940]

include/boost/fusion/algorithm/query/find_if.hpp

@@ -51,7 +51,7 @@ namespace boost { namespace fusion
     }
 
     template <typename Pred, typename Sequence>
-    inline typename result_of::find_if<Sequence const, Pred>::type
+    inline typename result_of::find_if<Sequence const, Pred>::type const
     find_if(Sequence const& seq)
     {
         typedef