Log Message:
Update to 2.23
all changes for pthai.el
- move to end of word after *insert *complete-word functions
- only toggle highlighting for 'pthai overlays
- various bug fixes, cleanups, and simplifications
- make end of word bounds detection more consistent
- add 'pthai-soundfiles-counts to display downloaded word counts per letter
- rename 'pthai-spell-string to pthai-spell-string-at-point, and
  'pthai-spell-word to pthai-spell-word-at-point
- rename pthai-overlay-off to pthai-hightlight-off