Switch to boost/serialization/pfto.hpp. Fixes #3061.
Merged revisions 48610 via svnmerge from https://svn.boost.org/svn/boost/trunk
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r48610 | dgregor | 2008-09-05 14:39:26 +0100 (Fri, 05 Sep 2008) | 1 line
Silence -Wunused warnings and switch to boost/serialization/pfto.hpp