forked from boostorg/range
as described in https://svn.boost.org/trac/boost/ticket/10754, postfix_increment_proxy and writable_postfix_increment_proxy were moved to boost::iterators::detail namespace
as described in https://svn.boost.org/trac/boost/ticket/10754, postfix_increment_proxy and writable_postfix_increment_proxy were moved to boost::iterators::detail namespace