Continue gradually replacing Boost.Lambda with Boost.Phoenix.

For some reason, after the upgrade to Boost 1.57, gcc 4.6.3 has trouble with
the boost::lambda::_1 usage in stringize.h. This is consistent with other
cases we've encountered in which Boost.Lambda appears to be unmaintained and
losing its compatibility with other libraries. Fortunately Phoenix provides a
functional equivalent, albeit spelled differently.