Bug in insert_node fixed: did not deal with the following correctly: qw/bcktx bckx bdix bdktx bdkx/ (The assymetry introduced by 'bdix' threw things off, or something like that).
Bug in reduced regexp generation (reinstated code that had been excised from _re_path() et al).
Rewrote the tests to eliminate the need for Test::Deep. Test::More::is_deeply is sufficient.