API changed! renamings:
  - some-romaji-sokuon -> some-romaji-sokuon-comp
  - some-kana-sokuon -> some-kana-sokuon-comp
  - some-sokuon -> some-sokuon-comp
added support for "\n\b\t\f\r" characters.
fixed bug with ッ.
fixed some mispositioned docstrings.
added Megumi Imai contribution notice.
replaced some unneeded calls of 'find-first' with 'some'.