Merge r86524 (Correct broken links to C++ standard papers); fixes #9212

git-svn-id: http://svn.boost.org/svn/boost/branches/release@86673 b8fc166d-592f-0410-95f2-cb63ce0dd405
Merge some changes to variant that accidentaly were not merged in r86650

git-svn-id: http://svn.boost.org/svn/boost/branches/release@86674 b8fc166d-592f-0410-95f2-cb63ce0dd405
Merge some more changes to variant that accidentaly were not merged in r86650 

git-svn-id: http://svn.boost.org/svn/boost/branches/release@86676 b8fc166d-592f-0410-95f2-cb63ce0dd405
Merge circular_buffer from trunk: 
* dropped support of antique compilers (thanks to Stephen Kelly for doing it all around the boost!)

git-svn-id: http://svn.boost.org/svn/boost/branches/release@86677 b8fc166d-592f-0410-95f2-cb63ce0dd405