* `word_boundary`, `word_boundary_left`, and `word_boundary_right` added to
  `regex_supplement` dictionary to provide a true word boundary.  Regexes
  adapted from: http://www.rexegg.com/regex-boundaries.html#real-word-boundary

* `youtube_id` was documented under `qdap_usa` rather than `qdap_supplement` and
  contained an invalid hyper reference.  This has been fixed.