(char_byte_table): Change name from "char-code-table" to

(char_byte_table): Change name from "char-code-table" to
"char-byte-table".
(mark_char_code_table): New function.
(char_code_table_equal): New function.
(char_code_table_hash): New function.
(char_code_table_description): New constant.
(char_code_table): New type.
(make_char_code_table): New function.
(copy_char_code_table): New function.
(get_char_code_table): Modify for `char_code_table' type.
(put_char_code_table): Likewise.
(vars_of_mule_charset): Update `utf-2000-version' to 0.12 (Kashiwara).