update boost to 1.52.0

need more recent version for compiler fixes/warnings, fixes, portability and other improvements
as of today, 1.53.0 is the latest version, but 1.52 is latest that builds without any modifications to the code.
Changelog can be found here: http://www.boost.org/users/history/
Merge branch 'master' into recent-libs
Merge pull request #108 from breznak/recent-libs

Recent libs - boost 1.52