Made datum_t::check_str_validity be static.
Added datum_t::null.
Made time_in_tz not use datum_ptr_t.
Removed datum_ptr_t from mock_namespace_interface_t::write_visitor_t point_replace_t method.
Removed datum_ptr_t for array case of pathspec.cc's .
Made object case of the pathspec.cc project function not use datum_ptr_t.
Removed a datum_ptr_t in wire_datum_map_t::to_arr.
Removed match_term_t array datum_ptr_t.
Made stats_merge not use a datum_ptr_t.
Made coerce_term_t not use a datum_ptr_t array.
Made distinct_term_t not use datum_ptr_t.
Made get_all_term_t not use datum_ptr_t.
Made make_array_term_t not use datum_ptr_t.
Removed use of datum_ptr_t in arr.cc.
Removed datum_ptr_t arrays in arith.cc.
Made datum stream array-like uses of datum_ptr_t be gone.
Made unproject not use an array-like datum_ptr_t.