cucul_set_color() and cucul_set_truecolor() under the new names
    cucul_set_color_ansi() and cucul_set_color_argb().
  * Renamed cucul_get_color_name() into cucul_ansi_to_str().

functionality into cucul_set_attr().
  * Add cucul_ansi_to_attr() and cucul_argb_to_attr().
  * Rename CUCUL_COLOR_* to CUCUL_*.

with cucul_set_attr_ansi(). Old application will still compile (but issue
    a warning) and run, though.

int which shall be used as an UTF-32 character. We do not have any casting
    problems due to the signedness of chars because all characters were
    ASCII (ie. <= 0x7f) beforehands.