raw_paged: add predicates _at_page_beginning() and _at_page_end()
raw_paged: add predicates _at_page_beginning() and _at_page_end()

biojppm/c4stl,biojppm/c4stl,biojppm/c4stl,biojppm/c4stl,biojppm/c4stl,biojppm/c4stl