Thread: add _back/_front using queue_op_status interface to sync queues and update the depending classes thread_pool and user_scheduler; Simplfy some test to isolate the errors on msvc-12.

git-svn-id: http://svn.boost.org/svn/boost/trunk@86616 b8fc166d-592f-0410-95f2-cb63ce0dd405
correct usage of codecvt_utf8

git-svn-id: http://svn.boost.org/svn/boost/trunk@86617 b8fc166d-592f-0410-95f2-cb63ce0dd405
corrected usage of codecvt_utf8

git-svn-id: http://svn.boost.org/svn/boost/trunk@86618 b8fc166d-592f-0410-95f2-cb63ce0dd405
Made perimeter algorithm variant-aware.

git-svn-id: http://svn.boost.org/svn/boost/trunk@86619 b8fc166d-592f-0410-95f2-cb63ce0dd405