[boost] Version mismatch on develop

On the current develop, autolink wants to link to (for instance) libboost_filesystem-vc80-mt-s-1_59.lib, but b2 builds libboost_filesystem-vc80-mt-s-1_58.lib. That's because BOOST_VERSION has been updated to 1.59 in boost/version.hpp, but is still 1.58 in Jamroot.