(Vcharset_ucs): New variable.

(Vcharset_ucs): New variable.
(Qucs): New variable.
(print_charset): Change design; use `CHARSET_CHARS' and
`CHARSET_DIMENSION' instead of `CHARSET_TYPE'.
(make_charset): Change signature to specify `chars' and `dimension'
instead of `type'.
(range_charset_code_point): Modify for 256^n-set.
(encode_builtin_char_1): Encode as `ucs' in default.
(Fmake_charset): Modify for `make_charset'.
(Fmake_reverse_direction_charset): Likewise.
(Fsplit_char): Use `ENCODE_CHAR' instead of `BREAKUP_CHAR' in
UTF-2000.
(complex_vars_of_mule_charset): Add coded-charset `ucs'; modify for
`make_charset'.