[boost] MPL and MPL core

Were the changes to MPL splitting it between a core and the rest of MPL supposed to be part of the upcoming release ? Because looking at MPL the 'master' branch is at the previous 1.57 release and there have been quite a number of changes to the 'develop' branch since then, much of it relating to the mpl/core split. The 'develop' regression tests for MPL look pretty green. I would like to get bruno Dutra's fix for MPL arity into the coming release as it has been thoroughly tested on 'develop', but I do not know whether or not all the other MPL 'develop' changes should go in 'master' although I suspect not.