- add doxygen file description
- revert Dic_chr / board_search patch
returning the character instead of the code
was a HUGE performance penalty
The dictionary must use codes, the board must be
made to use codes instead of dic using tiles.
- add Dic_char and Dic_char_lookup as temporary
fixes for board_search. Should modify Board and Cross class
instead.
- create dic_code_t type
