[geometry] added the (not yet finished) distance_info to extensions

git-svn-id: http://svn.boost.org/svn/boost/trunk@86538 b8fc166d-592f-0410-95f2-cb63ce0dd405
fixed compilation error

git-svn-id: http://svn.boost.org/svn/boost/trunk@86539 b8fc166d-592f-0410-95f2-cb63ce0dd405
Thread: unlock around the calls to continuations oe deferred future executions.

git-svn-id: http://svn.boost.org/svn/boost/trunk@86540 b8fc166d-592f-0410-95f2-cb63ce0dd405
[geometry] avoid warnings for member order

git-svn-id: http://svn.boost.org/svn/boost/trunk@86541 b8fc166d-592f-0410-95f2-cb63ce0dd405